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PHYTOPATHOLOGY 


OFFICIAL  ORGAN  OF  THE 
AMERICAN  PHYTOPATHOLOGICAL  SOCIETY 


W.  A.  Qrton 


EDITORS 


DoxALD  Reddick        G.  p.  Clinton 


W.  H.  Barre 
H.  R.  Fulton 
Ernst  Bessey 
VVm.  T.  Horne 


associate  EDITORS 

(\  W.  Edgerton 
H.  T.  Gussow 
K.  (\  Stakman 
V.  H.  Stewakt 


H.  P.  Harss 
H.  A  Kdson 
G.  M.  I^eed 

J.  1^.  HORKR 


BUSINESS  MANAGER 


(-■.  L.  Shear 


VOLUME  VII 


JANUARY-DECEMBER,  1017 


With  11  Plates,  and  So  Text  Fujukks 


• .  • 


>  ■ 


•  « 


PriJI.lSIIKD   FOIt  TIIK   SnciKTV 

Williams  &  Wilkixs  CnMr.v.w 

I^ALTIMOHK,   Ml). 


254048 


•  ••• 

•  •  • 


•  • 


•• 


•  • 


•  • 


•  •  •  .•    • 

•  •  *•    •• 
••  •/  •   •  • 

•  •    •  • 


•  • 


•  • 


CONTENTS  OF  VOLUME  VII 

No.  1.    February 

Jens  Ludwig  Jensen  (1836-1904).    F.  K0lpin  Ravn 1 

The  penetration  of  foreign  substances  introduced. into  trees.    W.  H.  Rankin.  .      5 

The  generation  of  aldehydes  by  Fusarium  cubense.    Albert  C.  Lathrop 14  • 

Does  Cronartium  ribicola  winter  on  the  current?    W.  A.  McCubbin.  .  * 17 

The  injurious  effects  of  tarvia  fumes  on  vegetation.    A.  H.  Chivers 32 

Sour  rot  of  lemon  in  California.    Clayton  O.  Smith 37 

A  disease  of  pecan  catkins.    B.  B.  Higgins 42 

Some  new  or  little  known  hosts  for  wood-destroying  fungi.    Arthur  S.  Rhoads  46 

Notes  on  Cronartium  comptonisB  III.    Perley  Spaulding 49 

Further  note  on  a  parasitic  saccharomycete  of  the  tomato.    Albert  Schneider  52 

Phytopathological  Notes 54 

Abstracts  of  paper  presented  at  the  Eighth  Annual  Meeting  of  the  American 

Phytopathological  Society,  New  York  City,  December  26-30,  1916 58 

Literature  on  American  Plant  Diseases 79 

No.  2.    April 

The  perfect  stage  of  Glceosporium  venetum.    W.  H.  Burkholder 83 

Puccinia  subnitens  and  its  aecial  hosts.    Ellsworth  Bethel 92 

Contributions  to  our  knowledge  of  the  white  pine  blister  rust.    W.  A.  Mc- 
Cubbin      95 

Species  of  Melampsora  occurring  upon  Euphorbia  in  North  America.    E.  B. 

Mains 101 

Recent  cultures  of  forest  tree  rusts.    James  R.  Weir  and  Ernest  E.  Hubert 106 

A  Rhizoctonia  of  the  fig.    J.  Matz 110 

Buckeye  rot  of  tomato  fruit.    C.  D.  Sherbakoff 119 

Noteworthy  Porto  Rican  plant  diseases.    F.  L.  Stevens 130 

Pycnial  stages  of  important  forest  tree  rusts.    James  R.  Weir  and  Ernest  E. 

Hubert 135 

Review 140 

Phytopathological  Notes 140 

Report  of  the  Eighth  Annual  Meeting  of  the  American  Phytopathological 

Society.    C.   L.   Shear 145 

Report  of  the  Berkeley  Meeting  of  the  Pacific  Division  of  the  American  Phyto- 
pathological Society.     W.  T.  Horxe 150 

Literature  of  American  Plant  Diseases 152 

No.  3.    June 

Studies  on  Bacterium  solanacearum.    E.  E.  Stanford  and  F.  A.  Wolf 155 

Sparassis  radicata,  an  undcscribed  fungus  on  the  roots  of  conifers.    James  n. 
Weir 166 


CONTENW 

Some  ehanflet  produced  in  strawberry  fruits  by  Rhisopus  nisrieans.    Nbil  £. 

Stb%'bns  asd  Low  A.  Hawkins  17S 

Witches-brooms  on  hickory  trees.    F.  C.  Stewabt ISo 

A  new  leaf-spot  disease  of  cherries.    Bmwrr  A.  RuDOLm 1k8 

Elister  spot  of  apples  and  its  relation  to  a  disease  of  apple  bark.    Dban  H. 

Rose 198 

The  pathoKenic  action  of  Rhisoctonia  on  potato.    H.  T.  Guasow 209 

Synthetic  culture  media  for  wood-destroying  fungi.    Ernest  J.  Pieper,  C.  J. 

Ilmi-HRET    AND   S.    F.    ACRBB    .  214 

Phy topathological  Notes  221 

Literature  on  Plant  Diseases  . .  228 

•  No.  4.    Ai'orHT 

The   cupraminonium   washm.    their   preparation,    biological    properties,    And 

application.    <).  Ri'tler  2.'i5 

IlacilluH  fnorulanii  N.  Sp.    A  Imcterial  organivm  found  associated  with  curly 

top  of  the  sugar  brct.     1*.  A.  lio.vcqrET 2f>9 

A  now  apparatus  for  aiicptic  ultrafiltration.     Hali-h  K.  Smith  .  2tK) 

Factors  nffrcting  the  |>araititiiim  of  Cstilago  Zco*.     F.  (i.  Pieiieibel 294 

Hclcrotium  bataticola.  the  cuune  of  a  fruit-rot  of  |M*pper8.    William  II.  Martin  .'tfK) 

A  Nc^trin  pnrn^itic  on  Norway  innplc.     NIel.  T.  Cook 314 

Phy  topathological  Notcii  .  'M*\ 

Literature  on  Plant  DiaoaNcs  32.3 

No.  5.    CKrroBER 

Alternaria  on  Datura  and  potato.     R.  D.  Randh  327 

Suacrptibility  of  non-citrua  plants  to  Hactcrium  Citri.     R.  A.  Jeiile  XV^ 

SotiK'  dii>r.'uM.*H  of  oconoiiiic  planta  in  Porto  Rico.     L.  K.  Mileh       .    .    .  3I.'> 

Tm-o  now  fon*tit  trre  ruata  from  the  northwcat.     H.  S.  jArKrtoN. .  .'i.V2 

Rolatjiin  of  toiii|)eraturv  to  the  gniwth  and  inf«*cting  |>owcr  of  Fiutariurii  Lini. 

W.  H.  TiHiiALK  3.Vi 

A  HiiiipU-  and  efT<*rtiv<*  method  of  pn»tocting  citruH  fruits  against  8tom-<*n(i  rot. 

JiiiiN  .M.  HoiiKiiH  A\i>  F.  S.  Karlk  3r»l 

Arthro|MMii«  iind  gafltcn)|>odM  aa  carri<*ni  of  ('ronartium  ribicola  in  gn*€ii  hc»uH<*H. 

<;.    FLirrn  <;raVATT  AND   RrMII   P.   MAk.HIIALI 'M\S 

Pri'iiiiiinary  n*|Nirr  on  the  vi*rtirnl  di.*<tribuiifin  of  Fuaarium  in  aoil.     .Minmk  W. 

TwLoK  ;17I 

Brii*f»T  .\rtii'l<"* 

Notr^  on  WfMMl-ilifit roving  fungi  which  grow  im  lM>th  ronifi*rou?<  un<i  dcridii- 
oii!t  tr*N'Fi      II.  Jami:m  H.   Wcir  379 

Thr  "pr.'U  iiii'thiHl  iif  :ip|ilying  ronrrntratrd  fonnaldi'liydt*  solution  in  the 

rontrol  iif  fint   Htniit.      K.  J.   IIahkkij.  3^1 

RrvifHii  3h| 

Ph\  lopnl  holiiiiir.il  \«itfi«  .HsS 

LitiTaturi' on  IMinr  Di^fuac^if  .    .  ^V.*3 

\t».    (i.       Dl.i'l.XlhKK 

A  twig%nd  N'af  diJ^iTi.-**-  of  K<-rri.i  j:i|Ninir:t      V.  K.  Stkw  \nt  3*.#9 

Thi;  rromn  r;ink«T  ili-**.-!**'  of  r**-*'      L    M.  .M^-^^^Ki  40** 


Contents 

An  epiphytotic  of  cane  disease  in  Porto  Rico.    John  A.  Stevenson 418 

The  effect  of  roentgen  and  ultraviolet  rays  upon  fungi.    H.  L.  Tbumbull  and 

J.  W.  HoTsoN 426 

Sclerotinia  Trifoliorum,  the  cause  of  stem  rot  of  clovers  and  alfalfa.    A.  H.  Gil- 
bert AND  C.  W.  Bexnett 432 

The  conduction  of  potassium  cyanide  in  plants.    John  A.  Elliott 443 

Reviews 449 

Phytopathological  Notes 449 

Literature  on  Plant  Diseases 455 


INDEX  TO  VOLUME  VII 

New  scientific  names  &re  printed  in  full-faced  type 


Abies,  amabilis,  140;  balsamea,  46,  314; 
concolor,  140;  grandis,  140,  379;  lasio- 
carpa,  379;  magnifica,  140;  nobilis,  140 

Abronia,  elliptica,  93;  fragrans,  92;  mi- 
crantha,  93 

Acalypha,  bachmeroides,  160 

Acer,  negundo,  445;  rubnim,  48;  sac- 
charin um,  48 

Agree,  S.  F.,  see  Piepbr,  Ernest  J. 

Acrosporium,  fasciculatum,  39 

Actinomyces,  scabies,  212 

Adiantum,  35 

iEcidium,  Abroniae,  93;  fumariacearum, 
93 

Ageratum,  conyzoides,  160 

Aegle,  glutinosa,  59 

Agriolimax,  agrestis,  369 

Agropyron,  smithii,  73,  226 

Alerodes,  citri,  132 

Alfalfa,  leaf  spot  of,  70;  lightning  injury 
to,  142;  stem  rot  of,  432 

Alsike,  70 

Altemaria,  63;  Citri  var.  Cerasi,  188; 
crassa,  329;  cucurbits,  196;  Solani, 
316,  327;  on  Datura,  327;  on  potato, 
327 

Amaranthus,  blitoides,  92;  retroflexus, 
92 

Ambrosia,  artemisisfolia,  157;  trifida, 
445 

Amelanchier,  alnifolia,  109 

American  Ph  ytopatho  logical  Soc'iety, 
abstracts  of  papers  presented  at  eighth 
annual  meeting,  145-149;  Report  of 
the  Pacific  Division,  150-151. 

Amsonia,  67;  cliate,  69 

Angular  leaf  spot,  of  cotton,  64;  of  cu- 
cumbers, 61 

Anthracnose,  beah,  61;  of  camphor,  59; 
cucumber,  62;  of  onion,  59;  raspberry, 
83 


Aplanobacter,  agropyri,  226 

Apple,  blister  spot,  198;  bitter  rot  of, 
132;  fruit-rot  of,  59;  Hypochnus 
ochroleucus  on,  130;  root-rot  of,  77, 
223;  rot  of,  76;  rough-bark  or  scurfy- 
bark  canker  of,  202;  scab,  76,  221 

Arachis,  hypogsa,  156,  160 

Arbutus,  menziesii,  380 

Armadillidium,  vulgare,  369 

Armillaria,  mellea,  175 

Arthropods,  carriers  of  Cronartium  ribi- 
cola  in  greenhouses,  368 

Aschersonia,  on  Guava,  132 

Aspidium,  35 

Aster,  67 

Atriplex,  canesccns,  93;  confertifolia, 
93;  hastata,  92 

Auerswaldia,  palmicola,  131 

Avocado,  Mycosphserella  persese  on,  350; 
Phyllachora  gratissima  on,  350 

Azalea,  viscosa,  32;  effect  of  tar  smoke 
on,  32 

Bacillus,  amylovorous,  75,  200;  calif orni- 
ensis,  285;  coli,  200;  coli  communis,  14; 
mesentericus  aureus,  285;  morulans, 
269 

Bacterium,  Citri,  58,  339;  Dianthi,  284; 
herbicola  aureum,  285;  Malvacearum, 
64;  mesentericus,  159;  Phaseoli,  61; 
solanaceanun,  155;  viridilividum,  392 

Bailey,  Ernest,  see  Jones,  L.  R. 

Banana,  disease  of  Cuban,  14 

Barley,  blight,  69 

Bean,  anthracnose,  61;  blight,  61,  65; 
Cercospora  canesccns  on,  349;  Di- 
morium  grammodes  on,  131 ;  Isariopsis 
on,  345;  loaf  blotch  of,  345;  loaf  spot  of, 
345;  mosaic,  60,  61;  root  rot,  61 

Begonia,  effect  of  tar  smoke  on,  35 

Bennett,  C.  W.,  see  Gilbert,  A.  H. 


u 


Index 


Bethel.  Kllawortii,  Pucciniasubiutens 

and  itjt  a<>cial  luMta,  92--4M 
B«tula.  lutca,  47.  48;  occidcntalis,  379 
BidcDfl.  hipinnata,  163 
Birch,  vHlow.  4K 
BiABY.  ( I.  H..  The  nhort -cycled  rromyccs 

of  North  America  (abstract),  74 
Bitter  rot,  of  apple.  132 
Bjerkandera.  aduMta,  47 
Black  heart,  of  orange,  190 
Black  H|Mit.  of  |M>pf>er.  (>3 
Blakk.    M.    a..    Cook,    Mkl    T.,    and 

H(*HWARZE.   (\   A.,   Studies  on   peach 

yellows  and  little  |>each  (abstract),  76 
Blatta.  orientalis.  370 
Blight,  on  barley.  69;  on  liean,  61,  65; 

on  rhcHtnut.  313;  on  eggplant,  60,  78; 

on  jM'arj*.  7.5;  on  |M)tato.  374 

BlistfT  }«|M»t.   of  HftplcM.    19S 

Blurne:t.  ImlHainifrra.  HiO 

Boletus.  rfir(»in.'i|N>H.  74;  frost ii.  74;  gra- 

cilij*.  71;  ind('t«t^UM.  74;  purpureus,  74; 

s(>eriiif«UM,  74 
B()N'(iri:T.   V.  A..   Baeilluj*  nionilans  \. 

Hp..  2iM>  2s«» 
BotrvtiH.  rin«T«':i.  '.i*M 
Brawiira.  oliTacru  var.  aeephnla.  141 
Bread  fruit,  runt  of.  131 
Br<m  K.  \\ .  .*^..  and  HiTH.  W.  A..  Con- 
trol of  ;ipplr  rtrub  by  bleaching  [m>w- 

der    :ib-tr.irt  •.  7»i 
Broniuh.   h<Mikcrianu.*<,   14.3;  marginatur*. 

60;  Mtrhi'uj*!?*.  ♦'»•.* 
BiMMiks.   Cii\HLKs.   and  ('o<»LKY,   J.   S.. 

Jf>nathnii   Mfwit    •jtlM*tnict  >.    7i):   TfUi- 

fienttun*  n*l:ition.*«  of  apple  rot   fungi 

(abstract   .  7»» 
Brom.'iili.'t.  drtiiiNftn.  161 
Bhows.  Xh.i.ik  a.,  a  b.'ict<TijiI  Hti'in  and 

leaf  iliM'aj'r  of  li'ttuci*    al»Mtra<*t  ■,  <».'{ 
Bt'KKii<»i.i»»  i(.   W.   I!..   Ii«'an  «lis<'aj««*M  in 

Nm  ^  ork  St«t«*  in  n»l»i    abstract  •,  61; 

TIm»    jK-rfrrt     f*tag»*    of    <  tlii-oM{M>riuni 

vem-tuin.  M  •»! 
Bl'Tl.l.H  (  K .  rh«'  ('(ipraiitiiioiiiuni  u  ;u*h«*M. 

Zl'f  Jt;s 
Buttf-rnut.  17 
Byakn.  L   I*  . 'rvl<*firliu«»  tntiri  on  \%hfat . 

•Vi;  n  ni'liiatodi-  di*i'a-«*  of  t\\r  da**h«>«'li 

and    it»   miitrol    \t\    hot    uatt-r    tr«-at- 

nirnt     abftrart    .  «»»i 


Cabbage,  wilt,  375 

Calendula,  officinalis,  32 

Calonyction,  67 

Camellia,  sooty  mold  on,  133 

Camfmnula,  68 

Camphor,  anthracnose  of,  59;  limb  can- 
ker of,  59 

Canfiytuft.  effect  of  tar  smoke  on.  32 

Canker,  of  camphor  trees,  59;  citrus,  58; 
Illinois,  205;  rough  bark  or  scurfy 
bark,  '202 

Canna,  rust  on,  132 

Capno<lium,  brasilicnsc,  134;coflreie,  134; 
footie,  134;  mangiferum,  134;  stella- 
tmn,  134 

Capsella,  burMa-pastoris,  92 

Ca|)«icum,  annuum,  160,  312 

(^arica,  papaya,  349 

Carpinus.  314 

Carrot,  lightning  injury,  142 

C'akhn'kk,  Ktbanks,  Do  the  bacteria  of 
angular  leaf  spot  of  cucumber  over- 
win  t<'r  on  the  seed?  (abstract),  61 

Carya,  illinoenHis,  42;  ovata,  185 

('aasava,  CercoH|)ora  hcnningsii  on,  349 

(*astanea,  dentata,  47 

Cai4t<»lleja,    angustifolia,    106;   miniata, 

C<*h'ry,   bartrrial   heart  wilt,  64;  crown 

rot.  t»l;  croun  n)t  wilt,  64 
Ct'phuh'ururt,  virrHceni4,  1.32 
Crrcospora.    Apii,    tV5;   cancHcenn,   .349; 

rotTra-.   .'ill*;  craasa.  .'i.*i5;  cruenta,  .'M6; 

Datura*.  .Ti.');  hcnningrtii,  319;  Hibisci, 

.'<r.»;  IbiridiH,  ,'i.37;  Lunaria',  .'i.37;  \ico- 

tiaiw.  .34s ;  Solaninigri,  .TJ7 
CfTcal  pathologists,  field  conference  of, 

4,7.3  4.'>4 
Charcoal  rot.  of  Hweet  |K)tatoe«,  312 
ClK'noiNNliuin.  alburn,  92;  glaucuni,  92; 

lanceoliituni,  \f2',  pagonuni,  92 
Cherry,    h'af    H|>ot,    7.*),     ISS;    witches- 

br<N>rn.*4  on.  1V» 
ChcMtnut.  Iilmht.  313 
Ciii\Mt>«.  A.  II..  The  injurious  efTectM  of 

T.-ifMi  furnr.M  on  vegetation.  32-»'ki. 
Chr\>Miri\  \.i.    Abietin,    78,    XVJ;    I*iceie, 

.'CiJ.  wiirii.  ii.K{ . 
( 'hr>-«»pM.M.  67;  niariana,  6S 
CitruM,  trifoliata.  .VJ,  .*i.'J9;  canker,  58 


Index 


ui 


Cladosporium,  Citri,  60;  cucumerinum, 

62 
Clavaria,  amethystina,  171;  aurea,  171; 

formosa,  171 
Cleome,  serrulata,  93 
Clover,  leaf  spot  of,  70;  Nigredo  fallens 

on,  70;  rust,  75;  stem  rot  of,  432 
Cnicus,  americanus,  44 
Coccomyces,  hiemalis,  75,  404;  KerrlsB, 

405 

COERPER,    FLOR*feNCE    M.,    SCe    JOHNSON, 

A.  G. 

Coffea,  arabica,  115;  liberica,  115 

Coffee,  Cercospora  coffeae  on,  349;  dis- 
eases of,  130 

Coleosporium,  Apocynaceum,  69;  deli- 
cat  ulum,  68,  225;  Elephantopodis,  66; 
Helianthi,  67:  inconspicuum,  68;  Ipo- 
mseae,  67,  132;  Laciniarise,  68;  Solida- 
ginis,  20,  68,  225;  Terebinthinaceae,  67; 
Vemoniae,  67 

Colletotrichum,  cereale,  450;  circinans, 
59;  falcatum,  423;  fructum,  59;  solani- 
colum,  226 

CoLLEY,  Reginald  H.,  Mycellinm  of  the 
white  pine  blister  rust  (abstract),  77; 
Pycnial  scars,  an  important  diagnostic 
character  for  the  white  pine  blister 
rust  (abstract),  77 

Collins,  J.  Franklin,  On  using  an 
ether  freezing  microtome  in  warm  and 
damp  weather,  222 

Colocasia,  esculenta,  66 

Commelina,  nudiflora,  35 

Comptonia,  asplenifolia,  49,  108 

Conifers,  Sparassis  radicata  on,  166 

Convolvulus,  67 

Cook,  Mel.  T.,  see  Blake,  M.  A.;  and 
ScHWARZE,  C.  A.,  Apple  scab  on  the 
twigs,  221;  A  Nectria  parasitic  on 
Norway  maple,  313-314. 

Cooley,  G.  S.,  see  Brooks,  Charles 

Coreopsis,  67;  dclphinifolia,  69;  lanceo- 
lata,  69;  major,  69;  major  semeri,  69; 
major  rigida,  69;  tripteris,  69;  verti- 
cillata,  69 

Coriolellus,  sepium,  47 

Coriolus,  abietinus,  46;  nigromargina- 
tus,  46;  prolificans,  46;  versicolor,  46 


Corn,  Phyllachora  graminis  on,  55,  131; 

smut,  73 
Corticium,  javanicum,  115;  Isetum,  115; 

ochralcucum,  113;  salmonicolor,   111; 

vagum.  111,  209 
Cotton,  angular  leaf  spot,  64;  lightning 

injury,  140;  rust  on,  133 
Corylus,  avellana,  52 
Cratsegus,  douglassi,  109,  223 
Cronartium,  cerebrum,  135,  450;  coleo- 

sporoides,    106,  135;   Coiflandrae,  135; 

Comptoniae,   17,  49,    106,    135;   Quer- 

cuum,  20;  ribicola,  17,  58,  77,  95,  135, 

225,  368.  391,  449 

Croton,  glandulosus  var.  septentrional  is, 

161 
Crown  canker,  of  rose,  408 
Crown  rot  wilt,  of  celery,  64 
Crown  rot,  of  celery,  64 
Cucumber,    angular    leaf   spot    of,    61; 

anthracnose,  62;  mosaic  on,  61;  new 

leaf  spot,  62,  scab  on,  62 
Cucurbita,  maxima,  32;  pepo,  32 
Cuprammonium  washes,  235 
Curly  dwarf,  of  potato,  71 
Curly  top,  of  sugar  beet,  269 
Currant,  Cronartium  ribicola  on,  17,  58; 

effect  of  tar<smoke  on,  32;  rust  on,  17, 

225 
Cycas,  revoluta,  44 
Cylindrocladium,  410;  scoparium,  409 
Cylindrosporium,  onKerria  japonica,  399 
Cystospora,  batata,  74;  Sacchari,  424 

Daedalea,    confragosa,   379;    heteromor- 

pha,  380;  unicolor,  379 
Dalbby,  Nora  E.,  Corn  disease  caused 

by  Phyllachora  graminis,  55 
Dale,  E.  E.,  see  Melchbrs,  L.  E. 
Damping-off,  of  tomatoes.  319 
Dasheen,  nematode  disetis?  of,  6(5 
Datura,  cornucopia,  160;  fastuos'i,  160. 

327;  ferox,   327;    incrnus,    327;    licvis, 

327;  metelloides,  160;  quercifolia.  327; 

stramonium,  327;   stramonium   gi>?an- 

teum,  327;  stramonium  inermis,  327; 

tatula,  65. 163.  327;  tatula  inermis.  327 
Davis,  W.  H.,  and  Johnson,  A.  G.,  The 

aecial   stage   of   the   red   clover   rust 

(abstract),  75 


^MAMhl 


IV 


Index 


Dianthuii.  incamata,  289 
DiEHL,  William,  see  Melhur,  I.  K. 
Dimerium,  fcrammodes,  131 
Diplocladitiin,  410;  cylindroflponun,  410 
Diplodia,    cacaoicola,    423;   Camphonp, 

60;  rot  of  citrim  fruits,  301 
Distichlifl,  spicata,  02 
Dothichiia,  populoa.  4^ 
DiRRELL.  W.  L.,  Notos  on  curly  dwarf 

nymptomson  Irish  potatoes  (abstract), 

71 

Karl,  F.  S..  seo  Kcmikrs,  John  M. 
Karly  bliKht,  on  Datura,  327;  on  potato, 

327 
I'}chino<iontium.  tinctoriurn.  170 
Kclipta,  alba,  1.57 
KixiEKToN,  (\  W.,  A  (rnomonia  on  ogj?- 

plant  (abstract).  78 
Kdhon.  H.  a.,  nn<i  S<-iirki.\kr,  Ohwald, 

A    malnutrition   diwiiMo  of   the    Irish 

|>otato  and  its  control  (abstract),  70 
I*>lwomi.  attacking  the  dasheen.  00 
Kionilant.    ( -olletotrichum    solanicoluin 

on.  2'2i)',  (»nomonia  on.  7K;  Lifchtnin^ 

injury  to.  1 10;  stem  blight  of,  00.  78; 

wilt  on.  227 
Klephantopus,  tomentosus,  07 
KlfvinKta.  mcKaloma.  47 
Ki.LioTT.  John  a.,  A  new  parasitic  slime 

mold  suitable  for  class  work  (alwitract ), 

74:  Thi>  conduction  of  |H)tassium  cya- 

nidi*  in  plants.  44.'i-448. 
Klymus.    americanus,    143;    canadeiutis, 

73;  condensatiis,  73;  rIaucus.  09,  73; 

macounii,  7Ii;  nibustus,  0!) 
Kndothia.  |>arasitica.  313 
F'riKcnm.  ranad«*nsis,  10.3 
Krvsiniiiin.  as|N*rum,  92 
Kupatoriijin.  OS 
Kuphorbia.   lOl ;  commutata.  101;  rypa- 

rissia}*.   101:  rxif^ua.   lOl;  falcata.   UT2; 

fCcrardiaria.  lOTi:  mutatis,   lOJi:  |M*pliiH. 

lot:  riibuHta.  101 
Kuti»tti\.  t«'ni'lla.  -7:{ 
Kuthaniia.    OS;    r:ir<»litiiari.'t,    OS;    Icpto- 

ri'phala,  *kS 
K\«»:i5»ru«i,  <'«Ta»i.  Isji 

FAfLWRTTIK,    It.    <\,     l)l«».»i«iiiiiiul|on    «if 


Bacterium  Malvacearum  (abstract), 
04 

Fern,  effect  of  tar  smoke  on,  .34 

Ficus,  133;  carica,  110 

Fields,  W.  S.,  Method  for  photograph- 
ing  plate  cultures,  388 

Fig,  Rhisoctonia  of,  110 

Flax,  359;  wilt,  375 

Fomea,  annoeus,  175,  210;  applanatus, 
217;  pinicola,  210,  420 

Forest  trees,  rust  on.  100,  135 

Formaldehyde  solution,  for  control  of 
oat  smut,  381 

FraRaria,  .32,  178 

Fromme,  F.  D.,  Tylenchus  tritici  on 
wheat  in  Virginia,  452 

Fromme,  F.  D.,  and  Thomas,  H.  E.,  A 
Xylaria  root-rot  of  the  apple  (ab- 
stract), 77 

Fruit  rot,  of  pepj>ers,  308;  of  tomato.  00 

Fi'LTON,  If.  H.,  Manual  of  Fruit  Dis- 
eases, Hehlkr.  Lex  U.  and  Whetzel, 
Hkrhert  HirK,  (Review),  :W0-388 

Fusarium,  conglutinans,  358;  cubense, 
14;  distribution  in  soil,  .374;  Lini,  .3.50; 
martii,  01 ;  oxys|K)rum,  .375;  radicicola, 
.375;  roseuin,  384;  Solani,  .375;  subula- 
tum,  .385 

(Ialloww.  H.  T.,  Newton.  H.  Pierce. 

143 
(ttiniMlerma.  Tsug:e.  47 
(lARDNKR.  M.  \V..  I)iss4'mination  of  the 

organism    of    cucuml)er    anthracnose 

tal>stract),  02 
(Iasten>fK»ds,     carriers    of    (Vonartium 

ribicola  in  gn*enhous«>s.  .'(08 
(teranium,  effect  of  tar  smoke  on,  .35 
(liblMTella.  saubinetti.  .'i8."> 
(iiLHKRT.  W.  \V..  Virulenrr  of  different 

strains  of  C-ladoMporium  rucumerinum 

(alwtrart  :,  02 
(tiLiiKRT.   A.   H.   and   Hknnktt.  C  W., 

.*>el«' rot i Ilia   Trifolioruiii.   the  caiisi*  of 

hti*ni  rnt   of  eloviT"  and  :ilfalfa,  4.32- 

112 
<;l\|)\%i\.  v.  K.  aiicl  HKDhh'K,  Donald, 

Siilfuritiic  <'«>ne«»rd  grain's  t<i  pn'vent 

|N)udrry  inildi'U    'abs^trart  •,  ♦!♦» 
(il<ro|M)rus.  coriehoiih'S.   IS 


Index 


V 


Glopophyllum,  hirsutum,  48;  trabeum,  47 

GlcDosporium,  Camphorse,  59;  Mangi- 
ferffi,  132;  venetum,  83 

Glomerclla,  85 

Gnomonia,  on  eggplant,  78 

Gondule,  rust  of,  132 

Grapefruit,  canker  on,  59        i 

Grape,  powdery  mildew,  66;  rust  on,  132 

Graphiola,  Phoenicis,  131 

Grasses,  rust  on,  73;  Scolecotrichum 
graminis  on,  69 

Gravatt,  G.  Flippo  and  Marshall, 
Rush  P.,  Arthropods  and  gasteropods 
as  carriers  of  Cronartium  ribicola  in 
greenhouses,  368-373 

Guava,  diseases  of,  131 

Gt'ssow,  H.  T.,  The  pathogenic  action  of 
Rhizoctonia  on  potato,  209-213;  The 
occurrence  of  Colletotrichum  cereale, 
Dothichiza  populea  and  Leptosphseria 
Xapi  in  Canada,  450;  A  thumb  clip  for 
use  with  magnifiers,  451-452 

Gymnosporangium,  nelsoni,  109;  tubula- 
tum,  109 

Hapalopilus,  gilvus,  47 

Haskell,  R.  J.,  The  spray  method  of 
applying  concentrated  formaldehyde 
solution  in  the  control  of  oat  smut, 
381-383 

Hawkins,  Lon  A.,  see  Stevens,  Neil  E. 

Hedgcock,  Geo.  G.,  Edible  and  poison- 
ous mushrooms.  W.  A.  "Murrill 
(review),  140;  and  Long,  W.  H.,  The 
aecial  stage  of  Coleosporium  Ele- 
phantopodis  (abstract),  66;  and  Hunt, 
N.  Rex,  The  Peridermium  belonging 
to  Coleosporium  IpomoDse  (abstract), 
67;  X  Peridermium  belonging  to  Co- 
leosporium Terebinthinaceaj  (ab- 
stract), 67;  An  alternate  form  for 
Coleosporium  Helianthi  (abstract), 
67;  Some  new  hosts  for  Coleosporium 
Solidaginis  (abstract),  68;  Some  new 
hosts  for  Coleosporium  inconspicuum 
(abstract),  68;  Notes  on  Razoumofskya 
campylopoda,  315 

Helianthus,  67;  annuus,  321,  445;  aus- 
tralis,  68;  decapetalus,  68;  divarica- 
tus,   68;   eggertii,    68;  giganteus,   68; 


.  grosse-serratus,  68;  hirsutus,  68;  mi- 
crocephalus,  68;  saxicola,  68 

Helminthosporium,  mayaguezense,  351 

Hemileia,  vastatrix,  130 

Hemlock,  sap-rot  in,  47 

Heterodera,  radicicola,  66 

Hickory,  44;  witches-brooms  on,  185 

HiGGiNS,  B.  B.,  A  disease  of  pecan  cat- 
kins, 42-45 

Honeysuckle,  effect  of  tar  smoke  on,  32 

Hordeum,  jubatum,  69,  73,  143;  nodo- 
sum, 69 

HoTsoN,  J.  W.,  see  Trumbull,  H.  L. 

Ho  WITT,  J.  E.,  Phytopthora  infestans 
causing  damping-off  of  tomatoes,  319 

Hubert,  Ernest  E.,  see  Weir,  James  R. 

Humphrey,  C.  J.,  see  Pieper,  Ernest  J. 

Humphrey,  H.  B.,  Puccinia  glumarum, 
142 

HUNGERPORD,    C.    W.,    SCe    JOHNSON,    A. 

G. ;  Puccinia  graminis  on  wheat  ker- 
nels and  its  relation  to  subsequent 
infection  (abstract),  73 

Hunt,  N.  Rex,  see  Hedgcock,  Geo.  G. 

Hypochnus,  ochroleucus,  130 

Iberis,  amara,  32;  umbellata,  337 

Impatiens,  balsamina,  161 ;  sultani,  163 

Indigofera,  arreeta,  160 

Inga,  laurina,  132 

Inonotus,  dryophilus,  48 

Ipomcea,  batata,  312;  lacunosa,  67;  pan- 

durata,  67;  triloba,  67 
Irpex,  lacteus,  379 
Isariopsis,  on  bean,  345;  griseola,  345; 

leaf-spot,  345 
Ischnoderma,  fulignosum,  47 

Jackson,  H.  S.,  A  species  of  Chrysomyxa 
new  to  North  America  (abstract),  78; 
Two  new  forest  tree  rusts  from  the 
northwest,  352-355 

Jagger,  Ivan  C,  Two  transmissible 
mosaic  diseases  of  cucumbers  (ab- 
stract), 61 

Jehle,  R.  a..  Citrus  canker  investiga- 
tions at  the  Florida  Tropical  Lab- 
oratory (abstract),  58;  Susceptibility 
of  non-citrous  plants  to  Bacterium 
Citri,  339-344 


VI 


Index 


Jbn'SEN,  Je\h  LrDWiu.  Biography  of.  1 

Jimson  weed,  leaf-Hpot  of,  327 

JoiiN'fuiN,  A.  13..  flee  TArBENiUNR.  J.  J. 

JoiiXfM>N.  A.  <t.  and  ("obkpck,  Flor- 
ENCK  M.,  A  bnctorial  blight  of  soy 
bean  (abntract ),  (&5;  and  HrNOERPORO, 
C  W.,  Scolecotrichum  graminis  on 
timothy,  orchard  graas.  and  other 
gramea  (abstract).  69;  see  Joneh.  L. 
R.;  see  Da  vim.  \V.  H. 

Jonathan  spot.  76 

JoNErt.  Fred  Reuel.  The  Pseudopexiza 
leaf  spot  diaeaiieH  of  alfalfa  and  red 
clover  (abstract).  70 

J^.VEM.  L.  R..  John  HON.  A.  (r.  and 
Reddy.  C.  S..  Bacteria  of  barley 
blight  «e4»d-bome  (abittrnct).  60;  and 
Bailkv.  Krnrht.  FrcMt  necronis  of 
pf>tato  tiib«*ni  (Hlmtrnrt).  71;  Light- 
ning injury  to  Knl«>.  14(^142 

Juglanit.  cinen*.!.  47 

Juni|M»ruH.  commiinii*.  1(K):  Hco|>uloruin. 
10!) :  virginianii,  46 

Kale,  lightning  injury  to.  140 

Keitt,  <J.  W..  S<M*<infl  pro^n*HH  rf|M)rt  on 
invcMtigtitiunH  of  Imf  H|Nit  f»f  chorrieH 
an<l  pluriiM  in  WiHcnuHiii  uilMtnict  •.  7.*) 

Kerri:i.  j:i|Hinif':i.  •'{{>!< 

Kochi:i.  Mcopiiria.  *.^2 

KRftt'T.  \V.  S.,  Ii:i<*ti*ri:il  (IiK«*tiM«>H  i»f 
ri'Irry  .ibsfnirf  .  t*\:  \Viiit4*nng  of 
S'pforiri  |M'f ro«*«'liti.i  v.'ir.  Apii  i:ih- 
Htr  11*1 '.  ti.'i 

Ku**hiii-ol:i.  I'iri.  I.'U;  <  lof*-*ypii,  l.'kJ 

Kuiii<|U:it.  r:ink('r  on,  .V» 

I^ariiii.'iri.'i.   67;  rjirlri.   6h:  «*lt*g:in!4.   i\S; 

rloiigat.'i.  t»H:  pHUnflorn.  6S;  MC'irioHji. 

6s :  MTi»tiii:i.  i'ts 
I^arix.  i-iin»iM»:i.   Uis.  .'{.V»:  liiririiia.   |0*»; 

f »rr K It'll trtliM.  UWt.  17»i.  .'il.'i.  .'l.V» 
L%Tiiii<>i*.  Ki.iiiJtT  (V.  Th*-  gfiuTHtion  of 

aldfhv<l«'«<  by  Ku-.'irtuiii  nikN^rifM'.  14-16 
I.^f  MiKht.  of  tig.  Il'i 
Ix*.tf  bl<t*rh.  of  iMMfi.  .{|-'i 
Id'tii'TMnt.  of  U  I II (it  wht'.'lt.  2JI 
lii'af  ••iNif.  nlf;ilf:i.  7M;  U-an.  Hi'r,  rhiTry. 

7.'i.     Iss.    «'liivir.    70:    curiiiiibtT.    «ij. 

Jtiii?«i>ii  ui'ftl.  .(.'7:  phifii.  7.'i:  |Mit.ito. 

•i.'7,  toin:tti>.  A27 


Lemon,  brown  rot.  37;  canker  on.  59; 

scab,  00;  sour  rot.  37 ;  stem-end  rot.  363 
Lentinus,  171 

Leniitcs.  heteromorpha,  380;scpiaria,  217 
liCpidium,  densiflorum,  02;  medium,  92 
liCptoHphvria,  Napi,  450;  Sacchari.  131, 

424 
Lettuce,  rot,  392;  Sclerotinia  libertiana 

on,  60;  stem  and  leaf  disease  of.  63 
Levin.  Kxra,  Control  of  lettuce  rot, 

392-393 
Lightning  injury,  alfalfa,  142;  ca^-mts, 

142;  cotton.  140;  eggplant.  142;  kale, 

141;    potatoes,     140:     radishes.     142; 

sugar  IxH't.   141;   to  sugar  cane,  317; 

tomato.  142:  turnips.  142 
Lima  Ijoan.  mtNtuic  on,  <K) 
Lime,  canker  on.  59 
Literatum  on  plant  diHeases.  79-SI ;  152- 

154;  •22S-2:M;  3*22-326: ;««-.««;  455-4450 
LoNti,  W.  If.,  Hi»e  Hkimmim'K,  (Jko.  (1. 
Ij4mic<*ra.  tnrtarica.  32 
Lunar ia,  biennis.  .'i.'i7 
Lyco|N*rHicum,  cerasifonne.  161 ;  esculen- 

turn.  52,  155;  pyrifonne.  161 


MarnH|M)rium.  cookei.  32S;  I>atunr.  :i3l; 
S«>lniii.  32S 

Mains.  K.  li..  .SjHTii'H  of  MeluinfMora  oc- 
curring U|Mm  Kuplif»rbia  in  North- 
America.  101-105 

Maij^mA,  J.  It..  w»e  Stkvkns.  F.  L. 

Muiidarin.  ranker  on,  59 

Mango.  Meliola  on.  132 

Manihot,  IXi;  utillisma.  349 

Maple.  4-H:  Nectria  paraHitic  on  Nor- 
wav,  313 

Mar:ii«inius.  S.icchari.  42 1 

Marigold.  efTi*ct  f»f  tar  sinok«*  on.  •i2 

Makhiiall.  Rihh  v..  »<•«'  (;i{\v\TT.  <l. 
Flippo 

Maktix.  Wii.i.i  \\i  If..  \  S<*hToriiini  di?*- 
v:\M*  of  |H'p|HT«<  ;ib'»tr;irt  i,  IV-I ;  SrK*n»- 
tiuin  li:il:itirol:i.  :{i)s  'M'2 

M:irtyiii;t.  proliowriilfa.  pil 

M\«*'»»:v.  L.  M..  The  crown  c:ink«T  •li?«- 
f:i?*i'  «if  row.  Mis  417 

M%T/.  .r.  A  Uhiz<M*toni:i  of  thr  fig. 
110  lis 


Index 


vu 


McClintock,  J.  a.,  Economic  hosts  of 
Sclerotinia  libertiana  in  tidewater 
Virginia  (abstract),  60;  Lima  bean 
mosaic  (abstract),  60;  Will  Spongo- 
spora  subterranea  prove  serious  in 
Virginia?  (abstract),  72 

Myrica,  calif ornica,  49;  carolinensis,  49, 
108;  cerifera,  49;  gale,  49;  inodora,  50; 
pumila,  50 

McCuBBiN,  W.  A.,  Does  Cronartium 
ribicola  winter  on  the  currant?  17-31 ; 
Contributions  to  our  knowledge  of  the 
white  pine  blister  rust,  95-l(X);  and 
Posey,  G.  G.,  Development  of  blister 
rust  aecia  on  white  pines  after  they  had 
been  cut  down,  391-392 

Melampsora,  101;  Euphorbiae,  101;  Eu- 
phorbise-dulcis,  101;  Euphorbiae-Eng- 
leri,  101 ;  EuphorbisB-Gerardianae,  101 ; 
Gehnii,  101;  Helioscopise,  101;  Me- 
dusae, 108;  monticola,  103 

Melanconium,  Sacchari,  423 

Melchers,  L.  E.,  and  Dale,  E.  E., 
Black  spot  of  pepper  (abstract),  63; 
Puccinia  triticina  Erikss.  Leaf-rust 
of  winter  wheat  causes  damage  in 
Kansas,  224;  see  Potter,  Alden  A. 

Melh^s,  I.  E.,  Notes  on  mosaic  symp- 
toms of  Irish  potatoes  (abstract),  71; 
and  Diehl,  William,  The  develop- 
ment of  the  aecial  stage  of  Nigredo  on 
red  clover  (abstract),  70 

Melia,  133 

Meliola,  Camellaj,  134;  Citri,  134;  fur- 
cata,  131;  Mangiferae,  132;  Psidii,  131 

Methods,  for  photographing  plate  cul- 
tures, 388;  for  the  differentiation  of 
pathogenic  fungi  in  the  tissues  of  the 
host,  389 

Microtome,  ether  freezing,  222 

Microstroma,  132;  album,  on  oak,  42; 
Juglandis,-  185;  Juglandis  var.  robus- 
tum,  45 

Miles,  L.  E.,  Some  diseases  of  eco- 
nomic plants  in  Porto  Rico,  34:V-351 

Mistletoe,  315 

Monolepis,  nuttalliana,  92 

Mosaic,  on  cucumbers,  01;  on  liiiui  bean, 
60;  on  pea  bean,  61;  on  potatoes,  71, 
72;  on  muskmclons,  01 


Mucuna,  160 

Murphy,  Paul  A.,  Seed  potato  certifi- 
cation in  Nova  Scotia  (abstract),  72; 
The  economic  importance  of  mosaic  of 
potato  (abstract),  72 

Murraya,  exotica,  339 

Mushrooms,  edible  and  poisonous,  140     • 

Muskmelons,  mosaic  on,  61 

Mycorhiza,  74 

Mycosphaerella,  Perseae,  350 

Myriogenospora,  132 

Nasturtium,  wilt  of,  160 

Naumov,    N.    a..    Intoxicating    bread 

(review),  384-386 
Necrosis,  of  potatoes,  71 
Nectria,  <;occinea,  314 
Nematode,  disease  of  the  dasheen,  66 
Nematospora,  Coryli,  52;  Lycopersici,  52 
Nicotiana,  160;  tabacum,  155 
Nigredo,  fallens,  70 
Norton,  J.  B.  S.,  Host  limitations  of 

Septoria  Lycopersici  (abstract),  65 
Nummularia,  discreta,  205 


Oak,  42,  74 

Oat,  smut,  381 

Oberly,  Eunice  R.,  (compiler),  and 
Smith,  Florence  P.,  Literature  on 
American  plant  diseases,  79-81;  152- 
154;  228-234;  322-326;  393-398;  455-458 

O'Gara,  p.  J.,  Notes  on  the  distribution 
of  the  bacterial  disease  of  western 
wheat-grass,  225;  The  occurrence  of 
Colletotrichum  solanicolum  O'Gara  on 
eggplant,  226 

Oidium,  citri-aurantii,  39;  fasciculata, 
39;  tigitaninum,  39 

Oospora,  citri-aurantii,  39;  fasciculata, 
39;  lactis,  40 

Okra,  Cerocospora  Ilibisci  on,  349 

Onion,  anthracnose,  of,  59;  pink  rot  of, 
59 

Oosporoidea,  citri-aurantii,  39 

Orange,  black  heart,  190;  canker  on,  59; 
sooty  mold  on,  13.3 

Osner,  CJko.  a.,  Preliminary  notes  on  a 

•  new  leaf  spot  of  cucumbers  (abstract), 
62 


VUl 


Index 


Palm,  diseaBes  of.  131 

PantomuruB,  fulleri.  369 

Papaw,  Pucciniopsifl  Caries*  on,  349 

Parsley,  Hclerotinia  libertiana  on,  60 

Parthcnium,  intern  folium,  67 

Paspalum,  132;  conjugatum.  351 

Peach,  brown  rot,  179;  little,  76;  yel- 

lowfi,  76 
Peanut,  rust  on.  132;  wilt,  156 
Pear.  bliRht.  75,  130 
Peean,  dineane  of,  42 
Pellicularia,  koleroga.  130 
Peltier,  (J.  L.,  boo  Stkvexh,  F,  L. 
Pennington,  L.  H..  Boleti  and  myco- 

rhtia  upon  foroBt  tnn^  and  an  unuBual 

mycorhiia  upon  white  oak  (abBtract), 

74 
Peony,  effect  of  tar  imioko  on,  32 
Pepper,  black  spot  of.  63;  fruit-rot  of, 

308;  Bclerotium  diBcaBo  of,  64 
Peridermium.  acicolum.  20.  68;  cameum, 

66;    cerebrum.   315;   delicatulum,   68; 

harkncBBii.  20.  315;  Helianthi,  67;  in- 

conapicuum,  68;  ipomcrfp,   67;  Btrobi, 

17.  225;  terebinthinaceum.  67 
Persea,  americana.  350 
Petunia,  160 
Pesiia  ciborioidefl.  433 
PharbitiB,  68;  barbixera.  67;  hederacca, 

67 
PhaaeoluB.  vulgaritt.  01 
Pheidolo,  anaataBBii.  'M\U 
Phyllachora,  KruniituM.   .Vi.    131;  grntiB- 

Btma,  ^i50 
PhylloMtictu.  hortorum.  7H;  ftolitaria.  202 
PhyBalift.  alkokongi.  161;  angulata,  160; 

craBBJfnlin.  160;  philadolphira.  160 
PhyBo|M»llft,  vitJH,  132 
Phy tophi  horn,  rnrtorum,    126;  crythro- 

B<»|»tira.   12«i;   inf««j«!an».  122.  262.  319; 

terreitria,  I'JO 
Picea.  cngf*liii:innii.  7s.  17«».  .'Ci2;  oxrolMa. 

47;  iiiorin<lii.  .V)2;  ruU'iiM,  47 

PiKMKlHKl..     F.    J.,    WM*    .STAKyA.V.    K.    ('.! 

FactorM  nfforting  th<*  paniHitiBni  of 
I'litilaico  «oa*.  21^1  .'Ul7 

PlEPKk.    KhNKHT   J..    Hi  \IPHIIKY,    C    .1.. 

and  AiMKF..  S.  F..  Synthetic  rultun* 
nic<iiii  ft»r  \%*MMl-<li'^trcninpc  fungi. 
21  f  '220 


Pierce,  Newton  B.,  Biography  of,  143 

Pierce,  Roy  G.,  Albany  conference  on 
white  pine  bliBter  rust,  54;  Early  diB- 
covery  of  white  pine  bliBter  ruBt  in  the 
United  States,  224;  see  Hpauloino, 
Perley 

Pine,  mistletoe  on,  315;  rust  on,  17,  58, 
67,  77,  95;  white,  17,  54,  58,  319;  yel- 
low, 140 

Pink  root,  of  onion,  59 

PinuB,  attenuata,  107,  140;  austriaca, 
49;  banksiana,  107.  137,  140,  315,  451; 
caribsa,  67,  68,  315;  clausa,  67;  con- 
torta.  49,  68,  106,  135,  140,  315;  coul- 
teri,  107,  315;  densiflora,  49,  315; 
divaricata,  49,  68;  echinata,  49,  67, 
68;  elliotii,  68 

Pithecolobium,  saman,  132 

Plant  diseaseB,  literature  on,  79--81,  152- 
154;  22H-234;  3*22-326;  393-398;  45S- 
458;  Porto  Rican,  66,  130 

Plasmopara,  viticola,  258 

Plectodiscella,  Piri,  90;  veneta,  91 

Pluchea.  indica,  160 

Plum,  leaf  spot,  75 

P(xl  blight,  on  Datura  fastuosa,  328;  on 
Datura  stramonium  inermis,  328;  on 
Datura  tatula  inermis,  328 

Polygonum,  aviculare,  92;  erectUITi,  92; 
ramofliBflimum,  92 

Polyi>oruB.  baBiiapidioilcB,  171 ;  berklcyi, 
171;  frondoBUB.  171;  goetzii,  171; 
Mylittae.  171;  Polyjwrus,  47;  rhino- 
cerotiH.  171;  sacer,  171;  Sapurema, 
171 ;  Bchwrinitzii,  426;  sulphureuB,  172; 
tulKTaster.  171;  umbellatus,  171 

PolvBtictUB,  abietinus,  380 

Poppy,  effect  of  tar  smoke  on,  32 

PopuluB.  acuminata,  353;  angustifolia, 
3.'>.'i;  balBamiffTH,  3.5.3;  tremuloides, 
108.  .rvl.  .380;  trichorarpa.  108.  223,  353, 
380 

Poria.  weirii,  176 

PonMliBculuB,  iM'n<iuliH.  47 

PoHKY.  (1.  O..  tH'V  M<<'riiBiN,  W.  A. 

PotaMitum  ryanidr.  conduction  in 
pl.HntM.  443 

Potato,  curly  dwarf,  71 ;  effect  of  tar 
Biiioke  on.  32;  leaf  roll,  72;  lightning 
injury    to,    140;   malnutrition   disease 


Index 


IX 


of,   70;  mosaic,   71,   72;   necrosis,  71; 

powdery  scab,  72;  Rhizoctonia  on,  74, 

209;  rot,  178  * 
Potter,  Alden  A.,  and  Melchers,  Leo 

E.,  Ecological  observations  on  Usti- 

lago  Zeai  (abstract),  73 
Pouzolzia,  160 

Prunus,  avium,  48;  ilicifolia,  191 
Pseudomonas,  Citri,  58;  fluorescens,  200; 

papulans,  200 
Pseudoperonospora,  133 
Pseudopeziza,  70 
Pseudotsuga,  taxifolia,  108,  176,  315,  380, 

426 
Pteris,  35 

Puccinia,  Antirrhini,  265;  triticina,  224 
Puccinia,  18;  Canns,  132;  glumarum,  73, 

142;  graminis,  30,  73;  graminis  tritici, 

73;   luxuriosa,   93;   rubigo-vera,    143; 

subnitens,  92 
Pucciniastrum,  pustulatum,  109 
Pucciniopsis,  Caricffi,  349 
Pycnoporus,  cinnabarinus,  47 
Pynis,  malus,  445 
Pythiacystis,  citrophthora,  37,  126 
Pythium  debaryanum,  126,  391 

Quamoclit,  coccinia,  67 
Quercus,'agrifolia,  20;  rubra,  107 

Radish,  lightning  injury  to,  142 

Rankin,  W.  H.,  The  penetration  of  for- 
eign substances  introduced  into  trees, 
^13;  The  control  of  white  pine  blister 
rust  in  small  areas  (abstract),  58 

Rands,  R.  D.,  The  production  of  spores 
by  Altemaria  Solani  in  pure  culture, 
316;  Alternaria  on  Datura  and  potato, 
327-338 

Raspberry,  anthracnosc,  83;  effect  of  tar 
smoke  on,  32 

Ravn  F.  K0LPIN,  Jens  Ludwig  Jensen,  1-4 

Razoumofskya,  americana,  140;  campy- 
lopoda,  315;  occidentalis  abietina,  140 

Reedy,  C.  S.,  see  Jones,  L.  R. 

Reddick,  Donald,  see  Stewart,  V.  B.  ; 
see  Gladwin,  F.  E. 

Rhamnus,  cathartica,  391 

Rhizina,  inflata,  175 

Rhizoctonia,  74;  crocorum.  111;  micro- 


sclerptia,  116;  Solani,  111;  of  the  fig, 
110;  on  potato,  209 

Rhizopus,  nigricans,  178,  391 

Rhoads,  Arthur  S.,  Some  new  or  little 
known  hosts  for  wood-destroying 
fungi,  46-48 

Ribes,  17,  32,  58,  77;  tenuifolium,  372; 
nigrum,  449 

Ridgwat,  Charles  S.,  Methods  for  the 
difTerentiation  of  pathogenic  fungi  in 
the  tissues  of  the  host,  389-391 

Rogers,  John  M.  and  Earle,  F.  S.,  A 
simple  and  effective  method  of  pro- 
tecting citrus  fruits  against  stem-end 
rot,  361-367 

Root  rot,  of  apple,  77,  223 

Roripa,  palustris,  93 

Rosa,  32 

Rose,  crown  canker,  408-417;  effect  of 
tar  smoke  on,  32 

Rose,  Dean  H.,  Blister  spot  of  apples 
and  its  relation  to  a  disease  of  apple 
bark,  198-208 

Rosenbaum,  J.,  and  Shapavalov.  M., 
Strains  of  Rhizoctonia  (abstract),  74 

Rough-bark  or  scurfy  bark  canker,  of 
apples,  202 

Rubus,  32;  idaeus  var.  aculeatissimus,  86; 
neglectus,  86;  occidentalis,  86 

Rudbeckia,  68 

Rudolph,  Bert  A.,  A  new  leaf -spot  dis- 
ease of  cherries,  188-197 

Rust,  92,  352,  368;  on  bread  fruit,  131; 
on  canna,  132;  on  clover,  75;  on  cot- 
ton, 133;  on  forest  trees,  106,  135;  on 
grapes,  132 ;  on  grasses,  73 ;  on  Gondule, 
132;  on  peanut,  132;  on  Pinus  resinosa, 
225;  on  sweet  potato,  132;  on  wheat, 
73;  white  pine  blister,  17,  54,  58,  77, 
95,  135,  224,  319,  368 

Ruth,  W.  A.,  see  Stevens,  F.  L.  ;  see 
Brock,  VV.  S. 

Salix,  cordata  mackensiana,  109 
Salpiglossis,  sinuata,  161 
Salsola,  pestifer,  92 
Sarcobatus,  92 

Scab,  on  apple,  76,  221 ;  on  potato,  72 
Sclerotium,  bataticola,  65,  308 
ScHWARZB,  C.  A.,  see  Blake,  M.  A.,  see 
Cook,  NTel  T. 


Index 


Schixanthus,  pinnatufl.  161 
Hchixophyllum,  rointnunp,  380 
HcHNciDEK.  Albeht,  Further  note  on  a 

parasitic   saccharomycet-e   of   the  to- 
mato. 52-53 
ScHKCiNKR,  Oswald,  see  Edson.  H.  A. 
8coleeotrirhuni,  graminis,  69 
Senecio.  6K 
Septoria.    Lyro|>orstci,    65;    petroselina 

var.  Apii,  65 
Hereh.  423 

Sesamuin.  orientate,  160 
Hhapavalov,   M.,  see  Ho8cnbai:m,  J.; 

Intoxicating  broad,   Nai'mov,    N.   A. 

(reviews  aS4-.WJ 
Siicrbakopk,    (\    I)..    Buckeye    rot    of 

tomato  fruit,  llD-129 
Silphiuin.  anKUstuin,  67;  asteriscus,  67; 

c(>rn|>osituni.   67;   dent  at  um,   67;   gla- 

hrurit.   67;  intcKrifoliuiii.   67;  pinnati- 

fidurn.  67;  trifol latum.  67 
Silvenlraad,  diHras<'  on  CofTea,  115 
Sisymbrium.  altlHuimum.  Ik'i 
Smith.  Clayton  <)..  Sour  rot  of  lemon 

in  California.  37-41 
Smith.     Fum»:\<K     P..     we    Oiikkly. 

KlNKK.  fl. 
SyiTH.  Halph  K..  a  new  apparatus  for 

aiM*ptir  ultrafiltration.  2tK>-2!)3 
Smut,  oil  corn.  73;  on  oats,  .'isi 
Snap     Iwan.     mosaic.     61;     Sclerotinia 

lib«'rtiaiia  oti.  M) 
Solaiium.    rantlincmw*.   6.'>.    163;   melon- 

Kcna.    157:  niKrum.    ItU),  .'Wl ;  tuU'ro- 

utiin.  3 J.  157,  17K 
S<»lidnKo.  r»7 
S<M>ty    iiifild^.    fin    (*amcllia.     \'X\:    on 

oraiiic*'.  1<{<'{ 

S<iphi:t.  |:iiiriata.  \r2 

Sour  rot.  of  ItMiion.  37 

S*»y   kn'tin     b;irt«Tial  bliuht   of.  Ik'* 

Spar:iN«in.  rn!»pa.  167;  hcrlM'^tii.  161»; 
laiTiinoM.i.  liV'J;  ridicats,  l(W'i:raiiioHa.l69 

Sp\t  i,i»iN<..  I'liiu.i.v  \ot«H  <»n  Cronar- 
tiuiii  Cniiiptotii:!'  III.  !'.»  51 :  K\i<icnn» 
of  ih«'  'tviT  uiiii«rm>:  of  Cronartium 
ribii'ola  alKftract  .  5s :  \«M'dU«  runt  on 
PiTiu-  n-finotia.  iri5:  and  PiKiu  i..  Hn\ 
it.  S':iti'  ami  National  <|uarantini'«< 
:»i:;tjn-f  tlir  wliit#-  |iin«'  bli»»t«T  ni-f,  3|0 


Spilanthes,  acmella,  160 

Spongospora,  subterranea,  72 

Sporobolus,  airoides,  93 

Squash,  effect  of  tar  smoke  on,  32; 
mosaic  on,  61 

Stakmax,  K.  C,  and  Piemeisel,  F.  J., 
A  new  strain  of  Puccinia  graminia 
(abstract),  73 

Stanford,  K.  E.  and  Wolf,  F.  A., 
Studies  on  Bacterium  solanacearum, 
155-165 

Stanleya,  pinnata,  93 

Stem  rot.  of  clovers  and  alfalfa,  432 

Stem-end  rot.  of  cirtus  fruits.  361 

Stercum,  frustulosum,  217;spathulatum, 
169 

Stkvenh,  F.  L.,  Noteworthy  Porto  Hican 
Plant  diseas(;s  (abstract).  66;  (ar- 
ticle). 1,30-134;  and  Hi-th.  \V.  A., 
Pkltikk,  (J.  L..  and  Mall<kh,  J.  U., 
()l>servations  on  |M>ar  blight  in  Illinois 
(abstract),  75 

Stkvknh,  Nkil  K..  and  Hawkins,  Lon 
A..  S<ime  changes  prcKluced  in  straw- 
U'rry  fruits  by  Uhizopus  nigricans, 
17H-184 

Stkvknhon,  John  A..  Lightning  injury 
to  sugar  cane.  317;  an  epiphytotic  of 
cane  <li»eaMe  irt  Porto  Hico.  4JS-425 

Stkwaht.  F.  ('..  \S  it(lH's-br<M>m8  on 
hickory  tn^^'H.    IV*  IS7 

Stkwakt.  V.  B..  A  twig  and  leaf  dis- 
fa>M*  of  Kcrria  ja|M»nica.  3t>{^  M)7;  The 
fM'H'nnation  of  (Vonartium  ribicola  on 
rurraiit,  H1M5();  and  UKi>i)irK.  Don- 
am*.  li<*an  mosiiic   iabHtract>.  61 

Stin>ella.  Havida.  131 

StrawlM»rrv,  effect  of  tar  smoke  on.  32; 
rot  of.  17S 

Stizolobium,  nivcum.  H>1 

Subulina.  o<'tona.  371 

Sugar  \H*i*\.  curly  top  of.  JtiO;  light- 
ning injury  to.  Ill 

Sugar  cam*.  ilisiM.***-.  lis;  leaf  spot  of. 
131;  linhtning  injury  t«».  317 

Suntloui-r.  elTiTt  of  tar  snn»k«"  on.  32 

S\Nr«f  p<»t:iio.  ihan*«»nl  rot  of,  312; 
< '>^to.^|lora  batata  on.  71;  rust  on,  132 

Svnt-dn'lla,  n<MliMt»r:i.  Hi() 


Index 


XI 


Tarvia  fumes,  effect  on  vegetation,  32 

Taubbnhaus,  J.  J.,  Two  new  camphor 
diseases  in  Texas  (abstract),  59;  and 
Johnson,  A.  D.,  Pink  root,  a  new  root 
disease  of  onions  in  Texas  (abstract), 
59 

Tatlob,  Minnie  W.,  Preliminary  re- 
port on  the  vertical  distribution  of 
Fusarium  in  soil,  374-378 

Tea,  disenfie  of,  132 

Tectona,  grandis,  160 

Thlaspi,  arvense,  93 

Thomas,  H.  E.,  see  Fromme,  F.  D. 

Thrinax,  ponceana,  131 

Thuja,  occidentalis,  47 

Timothy,  Scolecotrichum  graminis,  69 

TiSDALE,  W.  H.,  Relation  of  temperature 
to  the  growth  and  infecting  power  of 
Fusarium  Lini,  35^360 

Tobacco,  wilt,  155;  Cercospora  nico- 
tiansB  on,  348 

Tomato,  buckeye  rot  of,  119;  damping- 
off  of,  319;  fruit  rot  of,  60;  leaf-spot  of, 
327;  lightning,  injury  to,  142  parasitic 
saccharomycete  of  the,  52;  Phyto- 
phthora  infestans  on,  319;  wilt,  155 

Trametes,  camea,  380;  heteromorpha, 
380;  hispida,  380;  lacerata,  380;  peckii, 
380;  Pini,  176;  rubescens,  379;  serialis, 
380;  trogii,  380;  variiformis,  380 

Trichoderma,  lignorum,  424 

Trifolium,  hybridum,  70,  432;  incama- 
tum,  70,  432;  pratense,  70,  432;  repens, 
70,432 

Triticum,  vulgare,  73;  compactum,  73 

Tropseolum,  lobbianum,  161;  majus,  160; 
peregrinum,  161 

Trumbull,  H.  L.,  and  Hotson,  J.  W., 
The  effect  of  roentgen  and  ultraviolet 
rays  upon  fungi,  426-431 

Tsuga,  canadensis,  46;  caroliniana,  109; 
heterophylla,  108,  380,  426 

Tuberculina,  maxima,  139 

Turnip,  lightning  injury  to,  142 

Tylenchus,  tritici,  56,  452 

Tyromyces,  ca;sius,  47 

Uncinula,  necator,  66 
Uredo,  Artocarpi,  131 
Uromyces,  Arachidis,  132;  Dolicholi,  132; 
fallens,  70,  75;  JaniphsB,  133 


Ustilago,  Avenge,  381;  Isevis,  381;  Zeae, 
73,294 

Venturia,  pomi,  221 
Verbena,  erinoides,  161 
Verbesina,  67 
Vemonia,  67 
Verrucosis,  GO 
Volutella,  fructi,  59 

Walker,  J.  C,  Studies  upon  the  an- 
thracnose  of  the  onion  (abstract),  59 

Waite,  M.  B.,  Common  and  scientific 
names  of  plant  diseases  (abstract),  60 

Wandering-jew,  effect  of  tar  smoke  on, 
35 

Weir,  James  R.,  Notes  on  wood-de- 
stroying fungi  which  grow  on  both 
coniferous  and  deciduous  trees,  II, 
379-380;  and  Hubert,  Ernest  E., 
Recent  cultures  of  forest  tree  rusts, 
106-109;  Pycnial  stages  of  important 
forest  tree  rusts,  135-139;  New  hosts 
for  Razoumofskya  americana  and  R. 
occidentalis  abietina,  140;  Sparasis 
radicata,  an  undescribed  fungus  on 
the  roots  of  conifers,  166-177;  Note  on 
Xylari^  polymorpha  and  X.  digitata, 
223;  Cronartium  cerebrum  on  Pinus 
resinosa,  450-451 

Western  wheat-grass,  bacterial  disease 
of,  225 

Wilt,  cabbage,  375;  flax,  375 

Wheat,  Tylenchus,  tritici,  on,  56,  452; 
leaf-rust  of,  224;  rust,  73 

Wilt,  Bacterial  heart,  of  celery,  64; 
crown  rot,  of  celery,  64;  of  nastur- 
tium, 160;  of  peanut,  156;  of  tomato 
and  potato,  155 

Witches-broom,  on  cherry,  185;  on  hick- 
ory, 185 

Wolf,  F.  A.,  see  Stanford,  E.  E. 

Wood-destroying  fungi,  46,  214 

Xylaria,  polymorpha,77,223;  digitata,223 
Yam,  Cercospora  carbonacea  on,  351 

Zantho^ylum,  fagara,  339 
2iebrina,  pendula,  35 
Zygosporium,  oschioides,  350 


KHHATA  FOR  VOLUMK  VII 

Pa^o  4i^  line  27,  for  urtnlinospores  read  urediniospores. 

I'agc  113,  114,  and  115,  for  C(»rticum  read  Corticium. 

Pago  113  lino  9  and  page  114  line  4,  for  ochraUucum  read  oc/iro/cucum. 

Page  132  line  5.  for  CrphaUurujt  read  Cephaleuros. 

Page  134,  for  Illinois  Tniversity  read  University  of  Illinois. 

PaKo  1H4  line  7,  for  frum  rea<l  from. 

Page  ia3  line  1,  for  30  read  50. 

VHge  208,  section  6  of  Huinniary,  line  3,  for  diseases  read  diseased. 

Page  350.  legend  for  figure  3  should  read  Zygo»porium  anchxoides. 

Page  360,  370.  and  371,  in  table  headings  for  uredinospores  read  urediniospores. 

Page  370,  table  1,  column  K,  for  JG*  read  26. 

Page  .'Wi  line  10.  for  Tomasski  read  Pomasski. 

Page  3110  line  12,  strike  out  comma  after  water/ 

Page  418  line  1,  after  cane  insert  di.-ease. 


'         •*    ,    ■^ 


PHYTOPATHOLOGY 

VOLUME  VII  NUMBER  1 

FEBRUARY,  1917 

JENS  LUDWIG  JENSEN 
(1836-1904). 

F  .     K0LPIN    R  A  VN 

With  Portrait,  Plate  I 

The  introduction  of  "hot-water  treatment"  is  one  of  the  most  impor- 
tant steps  forward  in  practical  plant  pathology,  for  it  means  a  new  prin- 
ciple both  from  a  theoretical  as  well  as  from  a  practical  point  of  view. 
Therefore  it  will  surely  interest  the  readers  of  Phytopathology  to  be- 
come acquainted  with  the  originator  of  the  method,  because  in  it  we 
find  an  example  of  progress  due  to  a  man  from  practical  life,  who  had 
scientific  qualifications  as  well,  and  the  ability  to  carry  on  independent 
research. 

Jens  Ludwig  Jensen  was  born  January  9,  1836,  near  the  little  town  of 
Odder  in  the  Danish  province  of  Jutland,  where  his  father  was  forester. 
In  1855  he  passed  a  normal  school  examination  and  later  supplemented 
his  education  by  studying  natural  science.  He  taught  school  imtil  1872. 
In  1868  he  started  a  weekly  agricultural  magazine,  of  which  he  remained 
the  editor  imtil  1880,  and  from  1879  until  his  death,  he  was  the  publisher 
of  a  widely  circulating  advertiser. 

In  1872  Jensen  resigned  his  position  as  teacher,  and  together  with  a 
colleague  started  a  company  for  selling  scientifically  tested  seed.  This 
has  had  a  great  influence  on  the  development  of  modern  agriculture  in 
Denmark.  He  took  part  in  the  daily  routine  of  the  business  until  1881, 
and  remained  one  of  its  directors  until  1896. 

Jensen  never  held  any  official  government  position  but  he  managed 
to  arrange  his  practical  affairs  in  such  a  way  that  he  could  spend  much 
time  in  study,  and  in  1881  he  organized  this  work  as  a  private  statistical 
institute  which  he  called  Bureau  Ceres.  Its  object  was  a  systematic 
collecting  of  observations  made  in  practical  agriculture  and  an  experi- 
menting both  in  field  and  in  the  laboratory,  which  he  had  equipped  in 
his  private  home.     Although  many  of  Jensen's  methods  were  primitive, 


••  .••••  •  *  »      1       •      m  #•••••  •  • 

••'••••  ••••  %  ••*••'  '•••*•••  •* 

•      •••  »..••  •  ••••,.•  ••_•••  ••• 

•  •••  •••••••••  ••••*•*  ••••  ••  •• 

2  Phytopathology  [Vol.  7 

yet  his  work  is  so  exhaustive  and  original  that  his  investigations  of  potato- 
late-blight  fungus  (Phytophthora  infcsians)  and  smut  in  cereals  are  among 
the  most  important  contributions  to  our  knowledge  of  these  diseases. 
Jen8<»n*H  incentive  for  investigating  the  potato  disease  was  the  work 
done  by  his  company  in  introducing  new  varieties  of  potatoes  into  Den- 
mark. In  the  years  1878-1881  more  than  one  thousand  experiments 
were  made  in  all  pjirts  of  the  country  and  wliile  inspecting  these  Jensen 
had  an  opportunity  of  studying  the  appearance  of  the  disease  under 
various  conditioius.  This  suggested  infection  experiments  in  which  he 
studied  the  spread  of  the  infection  from  the  leaves  to  the  tubers  rjid 
more  particularly  the  ability  of  the  soil  to  retain  the  s|K)resof  the  fungus 
by  filtration. 

In  1882  Jeii.**en  published  \\\^  exixjriments  which  resulted  in  the  develop- 
ment of  a  methoil,  "protective  moulding/'  to  prevent  the  tulxjrs  from 
infection.  He  discovered.  tcK>,  that  by  postponing  digging  for  two  weeks 
after  the  wilting  of  the  top,  tul)ers  otherwi.se  subject  to  late  attacks  of 
the  du^ease  might  Im»  kept  from  infection. 

In  June  1882  Jen.*4en  U^gan  his  imi)ortant  exi)eriments  concerning  the 
influence  of  tem|)erature  on  the  development  of  the  fungus.  He  dis- 
covere<l  among  other  things,  that  this  could  not  grow  in  a  temperature 
of  under  5°(\  or  over  2-r(\  Therefore  the  storage  temjKTature  of  po- 
tatoi^s  during  the  winter  should  never  go  liigher  than  bW  These  ex- 
periments gave  Jen.**en  the  clue  to  understanding  why  the  fimgus  attack 
is  severe  only  in  temixjnite  (*limates,  and  he  formed  an  hypothesis  for 
explaining  why  the  iK)tato  di.*it*jise  was  not  o!)served  in  North  America 
and  KurofH*  before  1840.  First  then  was  the  development  in  the  means 
of  trans|M>rtati<»n  such  that  the  |)otatoes  from  the  plateau  regions  of  iSouth 
Ameri<*a,  the  original  home  of  the  |K>tato  an<l  the  potato  fungus,  might 
l)e  carric<l  .•io  (|ui('kly  through  the  tropical  zone  that  the  hyphae  in  the 
tulK»rs  di<l  not  die  on  the  way. 

In  ()(*tolMT  1882  Jeimen  succee<le<l  in  demonstrating  that  the  hyphae 
an<l  s|)on*s  which  were  found  in  and  on  the  dise:ised  tul)ers  could  \ye  killed 
by  applying  a  temi)eratun»  <»f  M)W  for  four  Jiours  to  the  potatoes  with- 
out affecting  their  germinating  iH)wer.  The  heat  must  1k»  applied  as  hot 
air  for  the  germinating  |H»wcr  sufTered  too  much  when  the  tubers  were 
immersed  in  hot  water. 

In  18K;J-1H8-1  JeiLK^'u  published  his  method  for  <lisinfecting  seed  jx)- 
tato«»s  by  heat.  When  this  was  wskhX  it  was  |)o.*isible  to  prevent  the  pri- 
nuirv  attacks  of  the  diM»ase  and  to  delav  the  se<*ondarv  attacks  at  least 
one  to  two  ww»ks. 

Until  )H>rdeaux  mixture  ap|M'ared  for  the  first  tune  in  188G  as  a  preven- 
tive of  disease.  Jeri.Hen's  system  for  fighting  the  jKitato  fungus  was  the 


1917)  Ravn:  Jens  Ludwig  Jensen  3 

best  established  method  both  practically  and  scientifically.  In  1886  his 
work  received  recognition  from  La  Soci6t6  Nationale  d' Agriculture  de 
France,  and  he  was  awarded  the  large  gold  medal  of  the  society. 

In  1885  Jensen  began  to  investigate  smut  in  cereals,  and  by  means  of 
cross-inoculation  experiments  he  succeeded  in  demonstrating  that  the 
old  well-known  species  Ustilago  segetum  should  be  divided  into  four  varie- 
ties which  he  named,  tritici,  avence,  hordei  nuday  and  hordei  tecta.  The 
distinctiveness  of  these  varieties  was  later  confirmed  by  the  mycological 
research  of  Rostrup,  Brefeld,  and  Kellermann  and  Swingle.  These  in- 
fection experiments  made  it  appear  most  probable  that  smut  on  barley 
and  oats  was  caused  by  infection  during  the  blossom  period  and  that 
the  smut  spores  (or  hyphae)  are  to  be  found  under  the  glumes  in  the 
ripe  kernels.  The  importance  of  the  r61e  played  by  infected  seed  was 
further  demonstrated  by  experiments  proving  the  impossibility  of  in- 
fection through  the  soil  and  manure. 

In  1887  and  1888  the  most  important  experiments  in  disinfecting  seed 
were  published.  Jensen  compared'  the  chemical  remedies  proposed  by 
others  (copper  sulphate,  sulphuric  acid,  quicklime,  salt)  with  the  hot 
water  treatment  he  himself  had  found.  He  first  applied  hot  air  during 
a  long  period  as  for  the  potato  fungus,  but  the  results  were  for  the  most 
part  unsatisfactory.  However,  an  experiment  made  in  the  summer  of 
1887  in  treating  oats  with  hot  water,  circa  55°C.  for  five  minutes,  resulted 
in  killing  the  sniut  without  affecting  the  germinating  power  of  the  oats. 
This  experiment  forms  the  starting  point  for  the  development  of  the 
"Jensen  hot-water  treatment." 

Jensen  now  made  this  interesting  observation:  Smut  in  barley  is  not 
to  be  killed  by  the  same  treatment  as  smut  in  oats,  but  if  damp  barley 
seed  has  been  subjected  to  a  temperature  of  53®C.  for  five  hours  in  a  corked 
bottle  the  smut  disappears.  Jensen  explained  this  phenomenon  by  sup- 
posing that  a  five  minutes^  immersion  in  hot  water  was  insufficient  to 
moisten  the  smut  germs  hidden  in  the  seed  and  that  they  therefore  were 
treated  in  a  dry  condition  which  could  not  occasion  their  death.  By  the 
slow  heating  of  wet  barley  the  moisture  had  time  to  penetrate  and  soften 
the  smut  germs  and  these  were  therefore  killed  by  the  temperature  ap- 
plied. If  this  were  true  Jensen  thought  that  smut  on  barley  could  be 
prevented  by  soaking  the  seed  in  cold  water  and  then  applying  the  usual 
hot-water  treatment  for  five  minutes.  Experiments  made  in  1888  proved 
the  truth  of  this  theory. 

As  we  see,  Jensen  had  now  discovered  two  variations  of  a  method 
according  to  which  all  forms  of  smut  on  cereals  might  be  fought.  He 
also  proved  that  hot-water  treatment  could  be  used  for  smut  on  Bromus 
and  Arrhenatherum  and  that  it  might  be  used  as  a  preventive  measure 
against  certain  types  of  damping-off  in  sugar  beets  and  mangels. 


4  Phytopatholoot  [Vol.  7 

Jensen's  method  won  and  deserved  much  recognition  both  in  Denmark 
and  abroad.  However,  it  was  a  great  disappointment  to  him  to  see  that 
many  farms  which  had  introduced  the  method  abandoned  it  later.  It  was 
too  complicated  for  general  practical  use  where  no  steam  was  available. 
Nor  was  he  successful  in  his  attempt  to  form  a  company  for  building  a 
factory  for  applying  the  hot-water  treatment  of  cereals  on  a  commercial 
scale. 

After  this  Jensen  discontinued  his  work  with  the  hot-water  treatment 
and  devoted  himself  to  experiments  with  chemical  remedies.  Among 
these  he  preferred  potassium  sulphide,  first  tested  by  Kellermann  and 
Swingle.  This  sul)stance  was  the  main  ingredient  in  the  so-called  Ceres- 
powder,  manufactured  by  Jensen  and  placed  on  the  market  in  1895. 
The  last  years  of  his  life  until  hLs  death,  August  10,  1904,  were  largely 
devote<l  to  exjieriments  with  this  remedy  and  agitation  to  bring  it  into 
practical  use. 

During  the  yean*  since  Jensen's  death  the  hot-water  treatment  has 
again  come  to  the  front.  In  connection  with  many  of  the  Danish  dairies 
and  breweries,  coojierative  institutions  have  l)een  established  for  dis- 
infecting Heed  with  hot  water.  During  the  past  year  several  seed  firms 
have  built  factory  plants  for  the  hot-water  treatment  in  combination 
with  a  plant  for  drying  the  seed.  The  seed  which  has  been  thus  treated 
is  sold  with  a  guarantee  for  its  freedom  from  smut  and  leaf-stripe  disease. 


THE  PENETRATION  OF  FOREIGN  SUBSTANCES  INTRODUCED 

INTO  TREES 

W.  H.  Rankin 

With  One  Figure  in  the  Text 

Meyer^  in  1808  succeeded  in  introducing  a  dyeing  liquid  into  the  roots 
of  a  small  tree  by  cutting  the  stem  and  immersing  the  upper  part  of  it 
in  the  liquid.  The  solution  penetrated  after  some  time  into  all  the  roots 
with  the  exception  of  their  tips  and  the  slenderest  rootlets. 

Boucherie*  about  1840  patented  his  method  of  preserving  timber  for 
building  purposes.  He  made  a  shallow  groove  around  the  tree  and 
covered  it  with  a  belt.  The  space  under  the  cloth  was  then  connected 
with  a  barrel  containing  the  preserving  liquid.  The  solution  was  absorbed 
and  ascended  to  the  branches  and  leaves.  Later,  he  modified  his  method. 
A  canal  two  centimeters  in  diameter  was  made  through  the  stem  and 
from  the  latter  cuts  were  made  with  a  saw  on  both  sides  as  far  as  possible 
without  allowing  the  tree  to  fall  over.  The  liquid  was  distributed  up  and 
down  the  stem.  The  area  saturated,  however,  decreased  rapidly  in 
breadth  in  the  downward  direction.  He  states  that  the  best  seasoit  for 
thorough  penetration  by  this  method  is  autumn.  It  is  doubtful  as  to  the 
meaning  of  the  expression  "thorough  penetration"  since  he  further  states 
that  if  there  are  hard  knots  or  rotten  spots  at  the  base  of  the  tree  the  whole 
strip  of  wood  above  them  did  not  become  saturated  at  all  and  the  same 
was  true  with  the  central  part  of  the  core  of  deciduous  trees. 

Hartig'  introduced  colored  solutions  iiito  the  growing  stems  of  treed. 
He  bored  two  holes  at  right  angles  to  each  other  in  the  trunk  and  intro- 
duced the  colored  solution  into  them.  It  was  carried  to  the  top  of  the 
tree  but  in  transverse  sections  made  of  the  tnink  the  coloring  of  the  wood 
was  not  uniform.  Only  those  vessels  directly  above  the  canals  were 
colored,  forming  a  cross  in  the  sections. 

*  Meyer,  J.  C.  F.  Naturgetreue  Darstellung  der  Entwickelung,  Ausbildung  und 
des  Wachsthums  der  Pflanzen  und  der  Bewegung  und  Functionen  ihrer  Safte.  Leip- 
zig.    1808. 

'  Boucherie,  M.  A.  Mdmoire  sur  la  conservation  des  bois.  Annales  de  chemie 
et  physyque  74:  113-157.     1840. 

Nouvelles  recherches  siir  la  conservation  des  bois.    Comptes  Rendus  12: 

337-339.     1841. 

*  Hartig,  T.  (Discussed  by  Shevyrev  1903:  6-7,  but  the  direct  citation  to  Hartig 
is  not  given.) 


6  Phytopathology  (Vol.  7 

Sachs*  in  experiments  on  the  rate  of  ascent  of  sap  in  woody  plants 
used  lithium  nitrate.  He  allowed  the  plants  to  absorb  this  through  the 
roots  and  found  the  lithium  present  at  intervals  along  the  stem  and  at  the 
tips  of  the  branches.  He  performed  laboratory  experiments  in  which  he 
showed  that  such  a  substance  as  lithium  would  progress  in  the  stem  almost 
as  rapidly  as  water  itself,  while  solutions  which  dye  the  cell  walls  along 
its  upward  coiu-se  do  not  rise  nearly  so  rapidly  nor  so  far,  since  they  are 
largely  filtered  out. 

Shev>Tev*  was  the  first  to  utilize  the  original  negative  tension  of  gases 
in  the  tree  as  a  force  for  distributing  the  introduced  foreign  substance. 
He  attributes  the  failiu-e  of  Hartig  and  others  to  get  penetration,  except 
immediately  above  the  incised  vessels,  to  the  neglect  of  this  factor.  His 
method  was  to  attach  a  funnel  or  half-funnel  to  the  tree,  fill  it  with  water 
and  then  make  an  opening  in  the  tree  with  a  chisel  or  auger,  underneath 
the  surfaw  of  the  liquid.  As  a  modification  of  this  he  devised  a  metal 
tulx;  which  wjis  jireviously  connected  with  a  reservoir  containing  the  feed- 
ing solution.  This  was  forced  at  one  end  into  the  bark.  The  other  end 
wa.s  closed  with  a  rul)l)er  stopjx^r  through  which  a  bit  was  inserted.  Thus 
when  the  lx>riiig  wjis  done  the  solution  from  the  reservoir  penetrated 
immediately  into  the  wound  and  the  sucking  jKJwer  due  to  the  negative 
tension  of  the  gii.**es  in  the  tree  was  utilized  to  pull  in  the  solution.  He 
states  that  by  this  method  the  dye  penneates  not  only  the  iierial  but 
also-the  radicate  i>jtrts  of  the  plant.  .\s  to  the  results,  he  states:  **The 
absorl)ed  li(|uid  luid  risen  to  the  top  and  colored  all  the  veins  of  the  leaves 
and  even  the  veiru*  of  the  !>orries  on  th(»  gra|K»  vine.  The  dye  could  be 
det<M'te<l  five  feet  Ik»1ow  the  surface  on  all  of  the  roots  of  the  birch,  apple 
and  itsh  trees.  Thus  the  first  part  of  the  problem  is  solved;  we  can  in- 
tnxluce  a  licpiid  in  a  <li!!sired  quiuitity  into  all  iMirts  of  a  tree. '*  Further 
he  states:  '*The  vessels  iiicise<i  in  the  licjuid,  al)«orl>ed  and  distributed 
it  to  all  parts  of  a  living  tree.  Only  the  pithy,  dead  portion  of  the  tree 
was  not  saturated  with  the  li(|uid  althougli  its  absorption  by  the  rays  oc- 
curred (with  an  oak).  The  li(|uid  entered  the  roots  as  well  as  the  leaves, 
twigs  and  fruit."  The  data  given  for  ea<*h  tree  fed  do  not  indicate  tliat 
he  obtaine<l  anything  more  than  the  satunition  of  the  sap  wood  and  bark 

•  Sarh?*,  J.  Kin  H«*itrag  xur  KcnritnifiK  livn  aurHtcMgendrn  Suftntrorii  in  trun»piri- 
nmivu  Pflanien.     .\rb.  lM»t.  Innt.  \Vuril»urK  2:  IIH-IM.     187S. 

*  Shi'vvrc'v,  Ivan.  <Kxtrara4lirati»  nutrition  of  <liMeaJ*ni  Xrvvn  with  the  aim  of 
curinic  thrni  and  (i«»j*tn»yinK  their  paruiiitejf. )  M.  Z.  and  (1.  I.  Foreatry  Dept.  Re- 
port to  Foreatry  Department  al>out  injuriouh  iiiHerts,  pp.  1-51.  1903.  (Roprintinl 
from  SeUk.     Khoi.  i.  LyetMiv.     VMKi:  5H  la'M 

(Supplement**  to  the  "Fxtraradirate  nutrition  of  <liHoaMe<l  trees  with  the 
aim  <if  runng  thefii  and  <le<«troviriK  their  (xiriudte?*".  i  Zemledelt<*heskala  Kaiota 
(Agrirultufal  (iaieti**     No-    .'{.    I.  .'>.  ft      ItKM.      ^Reprint  eonHuite<l.  pp.   1    \li). 


1917]  Rankin:  Penetration  op  Substances  7 

of  root  and  stem  and  the  leaves,  for  he  mentions  specifically  that  the 
medullary  rajns  in  the  case  of  a  single  oak  were  colored. 

Roth,*  Goff,'  Mangin,^  Mokrzecki,®  BoUey,^®  Simon,"  Fron,^  and  others 
have  fed  trees  with  various  types  of  solutions,  including  colored  and 
nutritive  substances.  The  majority  of  them  have  used  nutritive  salts  or 
poisons  in  anticipation  of  curing  physiologic  ailments  or  inhibiting  plant 
pathogenes  and  insects.  No  accurate  data  are  given  on  the  penetration 
except  that  the  solutions  in  many  cases  were  found  to  reach  the  leaves 
and  some  obtained  penetration  of  the  roots. 

choice  of  substances  for  experiment 

It  seems  from  the  very  nature  of  colored  solutions,  such  as  methyl 
blue  and  eosin,  that  they  would  not  be  suitable  for  determining  accurately 
the  greatest  possible  penetration  obtainable  by  introducing  a  foreign 
substance.  The  staining  quality  is  very  helpful  in  tracing  the  rate  and 
distance  which  the  substance  has  advanced,  but  at  the  same  time  much 
resistance  must  be  encountered  by  such  substances  and  finally  much  of 
the  original  quantity  absorbed  will  be  adsorbed,  filtered  out  and  chemi- 
cally united  with  the  different  plant  parts  which  it  will  stain.  The  utili- 
zation of  substances  such  as  the  lithium  salts  overcomes  these  disadvan- 
tages although  the  actual  ascent  is  not  visible.  The  salts  of  Uthium  are 
for  the  most  part  soluble  in  water,  they  are  not  used  up  rapidly  in  the 
metabolic  processes  of  the  plant  and  most  important  of  all  the  minutest 
trace  can  be  detected  with  the  spectroscope.  Lithium  nitrate  in  solution 
was  used  m  the  experiments  reported  below. 

*  Roth,  Carl.  (A  method  for  artificially  feeding  trees.)  Chem.  Ztg.  20:  344- 
345,  fig.  2.     1896. 

^  Goff,  E.  S.  The  application  of  artificial  root  pressure  to  recently  transplanted 
trees.    Wisconsin  Agr.  Exp.  Sta.  Ann.  Rept.  14:  272-282,  fig.  4.     1897. 

*Mangin,  L.  Sur  la  nutrition  et  la  defense  de  la  vigne  par  injection.  Jour. 
Agr.  Prat.  1898:  918-920. 

^Mokrzecki,  S.  A.  (A  new  method  of  healing  and  nourishing  trees.)  Vyest- 
vik  Tavr.    Zenistvo.  nos.  11  and  12.     1903. 

Uber  die  innere  Therapie  der  Pflanzen.    Zeitschr.  Pflanzenkr.  13:  257-265, 

fig.  1-5.     1903. 

*"  Bolley,  H.  L.  (Artificial  feeding  of  trees.)  Report  of  the  botanist.  North 
Dakota  Agr.  Exp.  Sta.  Ann.  Rept.  14: 42-58.  1903.  Ibid  16:  33-65.  1904.  Ibid  17: 
35.    1906. 

"  Simon,  J.  M.  (Hypodermic  injection  in  plants.)  Jour.  Soc.  Nat.  Hort.  France. 
(Abs.  in  Card.  Chron.  3:41:8.     1907.) 

"  Fron,  G.  (Contributions  to  the  study  of  the  injection  of  nutrients  into  fruit 
trees.)    Jour.  Soc.  Nat.  Hort.    France  4:  10:  54^59,  fig.  2.     1909. 


8  Phytopathology  [Vol.  7 

forces  aiding  distribution  in  the  tree 

There  seem  to  be  three  forces  which  must  be  depended  upon  for  the 
rapid  distribution  of  any  foreign  substance  throughout  a  tree.  (1)  By 
taking  advantage  of  the  negative  tension  of  the  gases  in  a  tree  in  the  sum- 
mer, when  transpiration  exceeds  the  intake  of  water  through  the  roots, 
the  solution  containing  the  substance  is  quickly  intromitted.  Undoubt- 
edly,  the  currents  set  up  by  supplying  this  ready  access  to  a  quantity 
of  liquid  ser\'e  to  distribute  the  substance  to  a  certain  degree.  (2)  Most 
important  of  all,  however,  are  the  translocating  streams  of  sap  in  the 
tree.  The  upward  movement  of  raw  sap  will  soon  carry  the  substance 
to  the  leaves  and  the  downward  movement  of  the  modified  food  materials 
in  the  phloem  will  undoubtedly  csLTiy  the  substance  back  down  to  all 
parts  of  the  bark.  The  constant  translocation  of  materials  between  such 
active  cells  as  phloem  parench>Tna  and  medullary  ray  cells  will  serve 
to  distribute  it  in  time  throughout  these  tissues  and  the  downward  move- 
ment of  modified  food  into  the  roots  would  also  be  expected  to  ultimately 
carry  the  substance  through  the  root  tissues.  (3)  Except  by  diffusion, 
which  is  a  ver>'  slow  process,  the  only  movements  which  can  be  counted 
on  to  distribute  the  substance  in  the  heart  wood  are  the  translocation 
currents  in  the  medullary  rays  and  the  alternate  withdrawal  and  renewal 
of  the  water  in  the  heart  wood.  The  water  in  the  center  of  the  tree  is 
said  to  act  as  a  reser\'e  supply  upon  which  the  tree  draws  during  the  day 
in  dry  weather.  The  normal  water  content  of  the  heart  wood  is  again 
restored  at  night.  It  wquld  apf)ear  then  that  such  an  oscillation  of 
currents  might  8er\'e  evei  tually  to  distribute  the  substance  throughout 
the  wood. 

In  other  words  there  is  no  reason  to  l)elieve  that  a  foreign  sul)stance 
intrcnluced  into  a  tree  cannot  penetrate  to  all  parts  provided  it  possesses 
certain  properties  in  itself. 

METHOD   OP   FEEDI.VG 

Ten  chestnut  trees  var>'ing  from  two  and  one-half  to  nine  inches  in 
diameter  wore  fed.  The  trees  were  growing  in  the  forest  and  had  small 
crowns.  Shevyrev*s  methods  with  slight  modifications  were  used  in 
the«<»  ex|)orinH»ntjt.  .\  haif-funnel  was  attached  to  the  tree  with  putty. 
The  funnel  wiis  then  fille<l  with  water  and  a  one-half  inch  hole  was  bored 
un<l(T  the  surface  of  the  water  with  a  bmce  and  hit.  The  hole  was  l)ored 
to  rrach  Xhv  c<»nter  of  the  tree.  .\  one-gallon  l)ottle  containing  the  lithium 
nitrate*  solution  had  previously  lK»en  suspended  so  that  the  l>otton  of  the 
Ijottlf  w'lin  slightly  hij^her  than  the  hole  in  the  trunk.  The  solution 
was  tlu'ii  connected  with  the  tree  by  means  of  a  siphon,  made  of  glass 


1917] 


Ranxin:  Penetration  op  Substances 


9 


and  rubber  tubing,  one^iuarter  of  an  inch  in  diameter.  In  order  to  keep 
out  air  and  prevent  the  leaking  of  the  solution  the  apparatus  illustrated 
by  Rumbold"  was  used.  The  rubber  siphon  was  connected  to  a  short 
piece  of  glass  tubing  inserted  through  a  one-inch  rubber  stopper.  In 
attaching  the  siphon  to  the  tree  the  solution  was  first  started  running  and 
as  the  half-funnel  was  knocked  from  the  tree  the  rubber  stopper  with 
the  glass  tubing  of  the  siphon  inserted  was  pressed  against  the  tree  so  that 
it  covered  the  hole.  The  end  of  the  glass  tubing  was  allowed  to  pro- 
ject into  the  hole  about  one  inch.  The  rubber  stopper  was  then  held 
firmly  against  the  tree  by  the  use  of  wooden  frames  and  a  piece  of  No.  8 
spring-steel  wire.  Thus  the  opening  was  perfectly  sealed  and  after  being 
once  properly  adjusted,  needed  no  further  attention.  The  glass  siphon 
tube,  reaching  to  the  bottom  of  the  bottle,  was  held  in  place  by  a  loosely 
fitting  stopper.  By  slightly  raising  this  stopper  a  new  supply  of  the  solu- 
tion could  be  poured  into  the  bottle. 


AMOUNT  AND   STRENGTH   OP  SOLUTION  PED   TO  TREES 

No  attempt  was  made  to  keep  careful  records  on  the  periodicity  of  the 
intake  *or  to  correlate  it  with  any  of  the  factors  influencing  the  rate  of 
intake.  The  accompanying  table  gives  such  data  as  were  taken.  Tree 
1  had  two  days  of  clear,  hot  weather  on  July  15  and  16,  when  it  absorbed 


TABLE  1 

Amount  of  lithium  nitrate  in  liters  of  solution  taken  up  hy  chestnut  trees 

TBBB 

I1R8T  FBBDINO 

BBOOND  rSBDINO 

THXBD    XBDXNO 

TOTAL 

KUIC- 

BBB 

0.002  per  cent 

0.025 
percent 

0.1  peroent 

0.1  percent 

Liters 

GraniM 

Jy.  16-16 

Jy.  16 

Jy.  16-20 

Jy.  90-26 

Jy.  26- A.  7 

A.  19-0. 10 

1 

3 

2 

2 

1 

2 

3 

13 

3.39 

2 

2 

1.5 
Jy.  16-17 

1.5 
Jy.  17-26 

1 

2 

8 

2.45 

3 

2 

i 

3.5 

2 

1 

12.5 

2.00 

4 

Jy.  17-18 

Jy.  18-26 

3 

2 

5 

5.00 

5 

1 

3 

2 

2 

3 

11 

5.58 

6 

3 

1 

4 

4.00 

7 

4 

4 

4.00 

8 

2 

2 

2.00 

9 

2.5  • 

2.5 

2.50 

"  Rumbold,  Caroline.  Report  of  the  physiologist.  Report  of  the  Pennsyl" 
vania  Chestnut  Tree  Blight  Commission,  July  1  to  December  31,  1912,  pp.45-47» 
figs.  39-49.     1913. 

Methods  of  injecting  trees.     Phytopath.  6:  225-229,  pi.  13.     1915. 


10  Phytopathology  [Vol.  7 

five  liters  of  solution  in  twenty-six  hours.  Then  followed  a  period  of 
cloudy  and  cooler  weather  which  caused  a  marked  decrease  in  the  amount 
absorbed  by  trees  1,  2,  3,  and  5  during  July  17  to  20.  The  largest  amount 
of  solution  was  absorbed  inmiediately  after  attaching.  Tree  2  absorbed 
two  liters  the  first  three  hours  and  tree  3  absorbed  five  liters  the  first 
nineteen  hours.  However,  the  hole  in  tree  3  reached  to  decayed  heart 
wood  and  the  punky  wood  absorbed  an  unusual  amount.  The  amount 
absorbed  diminished  rapidly  after  the  first  two  days  and  in  most  cases 
practically  ceased  after  the  fifth  or  sixth  day.  Trees  fed  the  second  and 
third  time  did  not  take  in  as  much  as  they  did  the  first  time.  The  in- 
creased strength  of  the  solution  used  in  the  later  feedings  may  hav^  ac- 
counted for  this.  However,  no  detrimental  effect  on  the  tree  was  ob- 
8er\'eil  and  the  one-tenth  per  cent  solution  allowed  the  feeding  of  a  suf- 
ficient amount  in  a  shorter  time.  After  the  feeding  on  August  13,  all 
the  trees  were  allowed  to  stand  until  October  10  so  that  a  chance  was 
affonliHl  for  more  complete  distribution.  The  leaves  were  just  begin- 
ning to  fall  when  the  trees  were  cut.  A  burning  of  the  margins  of  the 
leaves  occurred  in  the  case  of  the  smaller  trees  which  had  taken  up  as 
much  lithium  a.s  some  of  the  larger  trees. 

MFrrnoD  of  analysis  of  trees 

The  trees  were  cut  as  near  to  the  ground  as  possible.  Cross-sections 
about  one-half  inch  thick  weie  cut  from  the  base,  at  the  point  of  feed- 
ing and  ever>'  ten  feet  up  the  trunk.  A  few  leaves  were  taken  from  the 
to|>s  of  the  trees.  The  section.s  were  then  seasoned.  To  obtain  small 
block.s  from  these  sections  for  s[)ectroscopic  analysis,  a  strip  al>out  one 
centimeter  wide  was  sawecl  out  along  the  diameter  of  each  section.  Where 
the  bark  was  thick  the  cork  layer  was  separated  from  one  end  of  the  strip, 
starting  with  the  end  which  n»pR»sentod  a  iH)int  din^ctly  al)ove  or  lx*low 
thr  phuT  of  fet^ding.  This  >\*as  place<l  in  a  viiil  and  lalM^led.  Next  the, 
inner  bark  wjis  H]>lit  off  from  the  wood.  Then  a  small  block  alx)ut  one- 
half  reiitimeter  thick  n*pn»senting  the  sapw(K)d  was  cut  from  the  strip. 
Similar  blcM*ks  wen*  c\it  fmm  the  strip  at  intervals  of  al>out  two  centi- 
meters until  the  sapwcHHl,  inner  bark  and  cork  was  rea(^hed  at  the  other 
end  (»f  the  strip.  In  this  way  it  was  considen^d  tliat  representative  por- 
tions of  the  tree  wen?  obtain(*d  for  analysis  wliich  would  show  rather 
accunitely  X\u*  |)enetration  .s<Mnin»d.  The  l)lo(!ks  wen?  then  incinerated 
in  ran»fullv  clean(»<l  rniciblc*s  in  the  bunsen  fhiine.  The  ash  was  btuned 
on  a  platin\im  nc^edle  in  a  colorl(*ss  giis  fbme  and  the  spectrum  observed. 
Thr  pn»si»nce  or  alisena*  of  th<»  n»d  lithium  line  indicated  whether  or  not 
the  lithitim  had  |x»netnite<l  to  the  \mn  of  tlie  tree  represented  by  the 
block  U*ing  analy.sed. 


1917]  Rankin:  Penetration  of  Substances  11 

RESULTS 

The  results  obtained  were  practically  uniform.  The  blocks  in  which 
UtUum  was  found  are  shown  graphicaUy  in  Ulustmtions  1  to  9  in  figure  1. 
In  all  of  the  trees  except  3  and  6  complete  penetration  of  the  bark  and 
sapwood  was  obtained  at  and  above  the  point  of  feeding.  In  trees  3 
and  6,  for  some  reason,  the  lithium  did  not  penetrate  the  sapwood  on 
the  side  opposite  the  point  of  feeding.  In  all  the  trees  except  1  and  4 
the  lithium  had  completely  penetrated  the  sapwood  and  inner  bark  of 
the  sections  taken  at  the  surface  of  the  groxmd.  In  the  case  of  trees 
1  and  4  the  solution  had  penetrated  the  bark  and  sapwood  immediately 
below  the  point  of  feeding  but  did  not  appear  in  bark  and  sapwood  on 
the  opposite  side.  In  trees  1  to  6,  which  varied  in  diameter  from  5  to  9J 
inches,  the  Uthium  had  penetrated  the  heart  wood  only  in  a  few  cases, 
notably  the  basal  sections  of  trees  1,  3,  4  and  5  and  the  section  twenty 
feet  above  the  point  of  feeding  in  the  case  of  tree  2.  Tree  4  showed  more 
heart  wood  penetrated  than  any  of  the  others.  In  this  tree  the  heart 
wood  was  decayed  where  the  basal  and  breast-high  sections  were  taken 
and  the  bark  and  sapwood  of  the  basal  section  on  the  side  opposite  to  the 
point  of  feeding  was  not  penetrated.  However,  in  the  first  two  sections 
alcove  the  point  of  feeding  the  lithium  had  penetrated  for  at  least  two 
centimeters  inside  of  the  sapwood  in  sound  heart  wood.  In  the  case  of 
the  trees  of  smaller  diameter  (7,  8  and  9)  complete  penetration  of  the  en- 
tire wood  and  bark  was  obtained.  These  trees  (7,  8  and  9)  were  from 
2|  to  3  inches  in  diameter  and  contained  several  layers  of  heart  wood. 

The  leaves  and  twigs  from  the  very  tops  of  all  the  trees  showed  a  large 
amoimt  of  lithium  present. 

conclusions  from  data  obtained 

From  the  above  results  it  may  be  stated,  therefore,  that: 

1.  Lithium  nitrate  when  fed  to  chestnut  trees  by  Shevyrev's  method 
penetrates  to  all  places  in  the  tree  where  there  is  an  active  translocation 
of  food  materials,  that  is,  to  all  parts  of  the  bark  and  sapwood  above 
and  below  the  point  of  feeding. 

2.  Complete  penetration  of  the  heart  wood  is  obtained  in  trees  less 
than  three  inches  in  diameter.  In  trees  of  greater  diameter  the  process 
of  penetration  is  slow  and  does  not  seemingly  follow  any  definite  rule. 

Cornell  University 
Ithaca,  New  York 


12  Phytopatuologt  [Vol.  7 


EXPLANATION  OP  PIGURE  1 

The  fig:ur(«  rcfircAont  the  Atrip8  of  wood  bewchI  out  along  the  diameter  of  each 
croMHtertion  rut  from  tho  trees.  The  blockii  analyicd  are  shown  in  correct  pro- 
portion as  to  siie  and  position  in  the  strip.  Those  blocks  represented  by  shaded 
areas  Rave  positive  tests  for  lithium;  those  represented  by  white  areas  contained 
no  lithium.  All  the  figures  are  reproduced  to  a  scale  which  equals  one-fourth  the 
site  of  the  original  sections. 

The  sets  of  sections  are  numbered  according  to  the  trees  which  they  represent. 

The  sirctions  from  each  tree  are  lettered  as  follows: 

.4.   Section  from  base  of  tree  (at  ground)  • 

B.  Section  at  |>oint  of  feeding  (breast  high) 

C.  Section  ten  feet  above  B 
I).  Section  ten  feet  above  C 

E.  Section  ten  feet  al>ovc  D 

F.  Section  ten  feet  al>ovc  E 

(S.    I^*Aves  taken  from  top  of  tree 
When*  three  blocks  are  shown  at  the  ends  of  the  strips  they  represent  from  the 
outside  inmard.  cork,  green  bark  and  sapwood  respectively.     Where  only  two  are 
shown  they  rrpnttcnt  bark  and  sapwo<Ml. 


19171 


Rankin:  Penetration  of  Substances 


13 


inr 


I    II  II  II  1 

II   II  II  ir~rT 


TT-TT 


II     II     II 


II   ■   II    nnn 


mnr 


n 


II  II  II 


0 

c 
■ 


A 


r 


n 


II  II II 


IE 


IT 


'I     'I    II     II     !•■ 

e 


II     II     II      !■ 


A 
S 


n-p-TT 


i 


II    n    II 

••r 

A 
S 


n 


mi 


TTTT 


n 


n 


n 


IE 


TT— n 


II     II     n     rr 


Fig.  1.  Diagrams  Illustrating  the  Penetration  of  Chestnut  Trees 

WITH  Lithium  Nitrate 


THE  GENERATION  OF  ALDEHYDES  BY  FUSARIUM 

CUBENSE 

Klbert  C.  Lathrop 

The  possibility  of  aldehyde  occurrences  in  cultures  of  the  organism 
from  the  CuImui  banana  disease  Wiis  called  to  the  attention  of  this  labora- 
tory by  Dr.  (\  Rumlx)ld  localise  of  the  odor  accompanying  its  growth. 
The  possibility  of  aldehyde  production  by  the  fungus  was  further  suggested 
by  the  work  of  the  author  on  color  production  through  interaction  of 
aldehydes  and  certain  plant  constituents  in  connection  with  the  investi- 
gation of  humus  iKxlicH.  One  of  the  cliaracteristics  of  the  Cuban  banana 
disease,  whicli  according  to  Smith*  is  due  to  the  fimgus,  Fxisarium  atbense, 
is  the  purple,  purple-brown,  or  blackish  stain  produced  in  the  vascular 
bundles  of  the  dise^ised  banana  plant.  This  Fusarium  also  reddens  or 
purples  various  culture  media.  Numerous  experiments  carried  on  in 
this  lalx)rator>'  on  the  action  of  aldehydes  of  various  chemical  constitution 
in  respect  to  their  effect  on  plant  growth  have  demonstrate<l  that  alde- 
hydes are  uniformly  deleterioiLs  in  action.  The  generation  of  aldehydes 
by  Fusarium  cubettM'  might  therefore  account,  at  least  in  a  measure,  for 
its  pathological  action  as  well. 

In  reg]ird  to  the  generation  of  aldehydes  by  microorganisms  Grey'  has 
shown  that  acetaldehyde  is  a  product  of  the  action  of  B.  coU  cammuntM 
on  glu<*ose  muler  anaerobic  conditions.  That  acetaldehyde  is  a  product 
of  the  alcoholic  fermentation  by  yeast  was  discovered  by  Roeser,*  and 
more  recently  (\  Neul)erg  and  his  co-workers  have  very  fully  studied 
the  mechanism  of  this  reaction.  Neuberg  and  Hildesheimer^  have  shown, 
for  example,  tliat  acetaldehyde  is  pro<luced  by  the  action  of  yeast  on 
p\Tuvic  acid,  while  NeulM»rg  and  Kerb'  have  been  able  to  produce  propi- 
oni<'  aldehyde*  by  the  action  of  yejist  on  a-keto  but>Tic  acid. 

Tliat  aldehydes  are  generated  during  the  growth  of  Fumrium  cubenm 
on  synthetic  culture  media  was  experimentally  shown  in  the  following 
way.  Eleven  2-liter  Eriemneyer  fliisks,  each  containing  nhoui  seven 
hundred  cubic  <H»ntimeters  of  Tschinsky's  solution  were  sterilized  in  the 

» r^ivnce  81:  7.'>l  :.V>.     VMO. 
»  HiiK-hem.  Jour.  7:  :i"»!»  3t«.     I*»i:{. 
•Ann.  Innt.  pHMtnir  7:  41.     ls<J3. 
«Z«Mt.  phvHiol.  ('h<m.  31:  174.     HUl. 
•/>>it.  phyHiol.  ('hem.  47:  413  429.     1012. 


1917]  Lathrop:  Generation  op  Aldehydes  15 

autoclave  and  inoculated  with  a  pure  culture  of  Fusarium  cubenae  on 
May  28,  1915.  The  flasks  were  set  a§ide  in  a  dark  closet  and  the  Fusarium 
was  allowed  to  grow  at  room  temperature  until  January  21,  1916,  at  the 
end  of  which  time  the  Fusarium  was  still  growing.  The  liquid  culture 
media,  which  had  darkened  a  httle  and  which  had  taken  on  a  slightly 
penetrating  odor,  was  filtered  from  the  sediment  and  growing  Fusarium. 
The  clear  filtrate,  alkaline  in  reaction,  was  sUghtly  acidified  with  dilute 
sulfuric  acid  and  the  acid  Uquid  was  shaken  out  a  number  of  times  with 
ether  which  had  been  carefully  freed  from  aldehydes.  The  aldehydes 
were  removed  from  the  combined  ether  extract  by  shaking  with  a  freshly 
prepared,  saturated  solution  of  sodium  bisulfite.  The  bisulfite  solution 
was  then  acidified  with  dilute  sulfuric  acid,  the  sulfur  dioxide  removed 
by  aeration  under  a  long  ice  cold  reflux  condensor,  and  the  volatile  alde- 
hydes, boiling  under  75°,  were  separated  from  the  solution  by  fractional 
distillation,  and  collected  in  about  fifty  cubic  centimeters  of  ice  cold 
distilled  water.  The  aldehyde  fraction  so  obtained  was  then  treated  with 
a  httle  soUd  barium  carbonate  and  redistilled  in  order  to  hold  back  any 
volatile  acids.  This  distillate  was  tested  for  the  presence  of  aldehydes. 
A  few  cubic  centimeters  of  the  distillate  when  treated  withSchiflf 's  f uch- 
sine  aldehyde  reagent  gave  a  red  color  inunediately .  The  distillate  reduced 
anmioniacal  silver  nitrate  solution,  slowly  in  the  cold,  and  very  rapidly 
when  gently  warmed.  The  odor  of  the  solution  was  that  generally  given 
by  aldehydes,  especially  the  lower  aldehydes  of  the  aliphatic  series.  On 
boiling  a  little  of  the  solution  with  a  strong  solution  of  sodium  hydroxide 
a  pale  yellow  color  was  produced  which  disappeared  on  longer  heating, 

ft 

and  the  odor  of  the  solution  strongly  resembled  that  of  lemon.  This 
reaction  is  characteristic  of  propionic  aldehyde,  as  distinguished  from 
acetaldehyde  or  formaldehyde.  All  attempts  to  form  the  phenylhydra- 
zone  or  the  p-nitrophenylhydrazone  compounds  failed,  probably  owing 
to  the  small  quantities  of  the  aldehyde  which  had  been  obtained.  The 
aldehyde  in  the  remaining  portion  of  the' distillate  was  oxidized  by  means 
of  dilute  sulfuric  acid  and  potassium  permanganate  solution  to  a  volatile 
fatty  acid,  which  was  obtained  in  amounts  too  small  to  be  identified  by 
means  of  the  formation  of  the  metallic  salts.  By  the  method  of  obtain- 
ing the  aldehyde  the  fatty  acids  obtainable  by  the  oxidation  with  the 
acid  permanganate  mixture  are  limited  to  formic,  acetic,  propionic,  butyr- 
ic, isobutyric  and  trimethyl  acetic  acids.  The  odors  of  piu-e  hot  dilute 
solutions  of  formic,  acetic,  propionic  and  butyric  acids  are  so  suflSciently 
characteristic  as  to  be  readily  distinguished  from  each  other.  Hot  dilute 
solutions  of  these  acids  were  then  compared  with  the  solution  of  the  un- 
known acid  and  the  odor  of  the  pure  propionic  acid  and  of  the  unknown 
acid  were  so  exactly  similar  that  they  could  not  be  differentiated.    This 


16  Phytopathology  [Vol.  7 

would  indicate  that  the  volatile  acid  formed  by  the  oxidation  of  the  al- 
dehyde is  propionic  acid.  These  reactions  show  that  a  volatile  aldehyde 
is  formed  during  the  growth  of  Fusarium  cubense  on  Uschinsky's  solution 
and  that  this  aldehyde  may  be  propionic  aldehyde,  although  the  amount 
of  the  aldehyde  which  was  obtained  was  too  small  to  make  absolutely 
certain  its  identification  as  propionic  aldehyde.  The  solution  remaining 
in  the  flask  after  the  fractional  distillation  of  the  volatile  aldehydes  gave 
no  reactions  for  aldehydes  either  of  the  aliphatic  or  aromatic  series. 

A  badly  infected  banana  stalk  received  from  Trinidad  by  the  Labora- 
tory of  Plant  Pathology  was  examined  for  the  presence  of  aldehydes. 
The  stalk  was  finely  chopped  and  pressed  in  a  fruit  press,  and  the  juice 
so  obtained  was  examined  by  the  method  given  above,  but  no  aldehyde 
reactions  were  obtained. 

Since  propionic  aldehyde  is  a  very  volatile  compound  it  is  possible 
that  appreciable  quantities  were  formed  during  the  growth  of  the  Fusa- 
rium and  escaped  from  solution.  The  author  had  hoped  to  take  up  this 
question  and  also  establish  absolutely  the  identity  of  the  aldehyde  formed, 
but  circumstances  do  not  permit  of  this  at  present.  The  observations 
made  seemed  of  sufficient  interest  to  call  to  the  attention  of  other  workers 
on  this  subject.  The  author  wishes  to  thank  Dr.  Caroline  Rumlx>ld 
and  Miss  Florence  Hedges  for  their  kindness  in  growing  the  Fusarium 
and  for  furnishing  the  diseased  and  healthy  banana  stalks. 

U.  8.  Department  op  Agriculture 
Washington,  D.  C. 


DOES  CRONARTIUM  RIBICOLA  WINTER  ON  THE 

CURRANT? 

W.    A.    McCuBBIN 

With  One  Figure<in  the  Text 

In  the  literature  at  the  writer's  disposal  very  little  mention  has  been 
made  of  the  over-wintering  of  Cronartium  ribicola  on  the  currant. 
In  a  few  cases  there  has  been  a  suspicion  of  over-wintering  on  this  host 
but  either  the  evidence  was  too  meagre  to  be  satisfying,  or  else  other 
facts  appeared  later  to  explain  the  circimistances  so  that  the  general' 
opinion  at  present  favors  the  entire  dependence  of  the  currant  stage  on 
a  yearly  infection  from  the  pine. 

In  some  of  the  records,  however,  there  are  mentioned  puzzling  occur- 
rences of  the  rust  on  ciu'rants,  either  at  long  distances  from  pines,  or  in 
circimistances  otherwise  so  suspicious  as  to  suggest  that  the  fungus  might 
have  passed  the  winter  on  the  currants  themselves.  Spaulding  (5a)  has 
mentioned,  in  connection  with  the  distribution  of  the  Peridermium  stage 
that  judging  from  analogy  with  Cronartium  CompUmiae,  the  spores  of 
which  are  similar  in  size  and  shape  to  those  of  P.  strobiy  it  is  probable 
that  the  latter  would  be  blown  only  relatively  short  distances;  but  he 
records  two  cases  in  which  no  diseased  pines  were  to  be  found  near  rusted 
currants.  In  another  article  the  same  author  (5)  lists  a  reference  to  an 
observation  made  by  Nilsson  in  1893,  where  rusted  Ribes  were  found 
over  three  quarters  of  a  mile  from  any  pines. 

Eflforts  have  been  made  to  settle  the  question  experimentally,  both  by 
planting  out  badly  rusted  currants  in  a  disease-free  neighborhood  after 
wintering,  and  by  inoculation  with  over-wintered  spores.  So  far  as  is 
known  the  latter  method  has  given  only  negative  results.  The  former 
method  was  employed  by  Stewart  and  Rankin  (9)  using  five  hundred 
rusted  currant  plants.  None  of  these  developed  any  rust  during  the 
succeeding  summer,  and  the  conclusion  is  drawn  that  the  fungus  rarely, 
if  ever,  over-winters  on  the  currant.  In  1914  Spaulding  (6),  in  recording 
the  negative  results  from  similar  experiments  with  two  hundred  plants, 
says,  "The  practical  conclusion  is  that  Ribes  plants  do  not  carry  the 
fungus  over  the  winter  and  that  an  outbreak  of  this  disease  on  Ribes  is 
to  be  attributed  to  the  presence  of  neighboring  white  pines  which  have 
the  blister  rust." 


18  Phytopathology  [Vol,  7 

In  a  former  article  (3)  the  writer  has  detailed  some  of  the  circumstances 
of  the  Ontario  outbreak  which  engendered  a  suspicion  that  the  rust  in 
question  might  have  ])as8ed  the  winter  on  currants,  and  in  the  work  with 
this  disease  in  1916  additional  evidence  has  appeared  to  strengthen  this 
suspicion.  The  evidence  at  present  available  can  not  be  considered 
sufficient  to  establish  the  point  beyond  question,  but  it  is  important 
enough  to  be  worth  careful  consideration. 

In  the  discussion  following  several  points  which  have  a  bearing  on  the 
question  are  considered:  (1)  A  hypothesis  to  account  for  the  various 
phenomena  observed.  (2)  Agreement  of  this  hypothesis  with  known 
conditions  in  other  rusts  of  a  similar  nature.  (3)  The  general  and  irregu- 
lar appearance  of  the  currant  stage  over  large  areas  in  which  there  is 
reason  to  believe  no  pine  infections  are  responsible  for  the  disease.  (4) 
Special  cases,  where  rust  has  occurred  on  currants  which  are  far  distant 
from  any  possible  source  of  infection.  (5)  The  occurrence  of  currant 
rust  in  one  instance  on  two  out  of  four  plants  in  a  plantation  in  which 
the  same  four  plants,  and  these  only,  were  badly  diseased  in  the  preced- 
ing year.  (6)  The  occurrence  of  a  case  of  currant  rust  on  plants  set  out 
in  a  rust-free  district  in  order  to  test  over-wintering. 

1.   HYPOTHESIS  TO  ACCOUNT  FOR  VARIOUS   PHENOMENA   OBSERVED 

On  account  of  the  difficulty  arising  from  the  loss  of  all  the  currant  leaves 
in  the  fall,  thus  separating  the  fungus  from  its  host,  no  satisfactory  hy- 
pothesis has  been  brought  forward  to  account  for  suspected  cases  of  hi- 
bernation. Spaulding  (1911)  has  suggested  the  possibility  of  this  hiber- 
nation, and  has  put  for\^'ard  the  idea  of  a  hil>emating  mycelium,  justify- 
ing it  by  reference  to  ol)served  cases  where  pustules  of  Puccinia  occurred 
on  currant  shoots.  The  presence  of  Cronartium  ribicola  in  such  suspicious 
locations  docs  not  seem  to  have  been  established,  although  the  same 
author  (5a)  records  the  finding  of  the  telial  stage  of  Cronartium  ribicola 
on  |)etio]es  and  stipules  of  Ribes. 

Judging  from  ol)servation8  made  during  the  last  two  years,  the  only 
hy|)othosis  which  seems  to  account  for  all  the  ol)serv'ed  phenomena  in 
connection  with  supi)Osed  cases  of  wintering  over,  is  the  hibernation  of 
the  mvcelium  in  infected  buds. 

A  feature  of  the  disease  previously  mentioned  by  the  writer  (3)  has  an 
im|K)rtant  l)earing  on  this  phase  of  the  question:  Early  and  complete 
defoliation  by  the  rust,  followed  by  a  secondary  production  of  leaves, 
due  to  the  premature  o|)ening  of  winter  buds.  It  has  often  been  observed 
that  such  secondarj'  leaves  are  also  rusted,  even  when  they  are  only  par- 
tially opened,  and  considering  tliat  the  incul)ation  period  of  the  fxmgus 


1917]  McCubbin:  White  Pine  Blister  Rust  19 

is  from  ten  days  to  two  weeks  or  more,  it  must  be  evident  that  infection 
can  take  place  very  close  to  the  bud  stage,  perhaps  as  soon  as  the  bud  scales 
are  parted  enough  to  expose  the  young  leaves  within.  Now  in  the  case 
of  a  shoot  producing  secondary  leaves  in  this  way,  the  terminal  bud 
opens  first  and  makes  most  growth;  the  one  next  below  it  opens  to  a 
lesser  extent;  and  those  farther  down  exhibit  diminishing  degrees  of  ac- 
tivity, until  towards  the  base  of  the  shoot  buds  are  foimd  which  still  re- 
main in  a  quite  dormant  condition.  It  is  true  that  leaves  produced  in 
this  way  from  buds  opening  late  in  the  fall  are  killed  by  the  first  severe 
frost,  and  often  several  of  the  uppermost  buds  also  perish,  but  some  of 
these  forced  buds,  without  doubt,  are  able  to  survive  the  winter. 

The  fact  that  each  shoot  producing  secondary  leaves  has  its  buds  ar- 
ranged in  a  series  extending  from  the  fully  opened  condition  to  the  dormant 
state,  shows  that  there  is  ample  opportunity  for  such  a  favorable  com- 
bination of  circimistances  to  occur,  while  the  actual  presence  of  the  rust 
on  very  young  leaves  is  evidence  of  the  capability  of  the  fungus  to  infect 
at  this  season  of  the  year.  The  only  step  that  need  be  taken  outside  the 
realm  of  fact  concerns  the  assimiption  that  an  infection  can  take  place 
early  enough  in  the  development  of  a  bud  to  still  leave  it  capable  of  pass- 
ing the  winter. 

The  field  conditions  demanded  by  the  above  hypothesis  are  quite  ade- 
quate for  the  purpose.  The  early  defoliation  mentioned  is  general  in 
some  plantations,  and  in  a  large  percentage  of  others  a  smaller  or  larger 
area  of  plants  lose  their  leaves  in  midsummer  on  account  of  rust  starting 
from  one  center.  The  total  number  of  such  cases  where  secondary  foliage 
has  been  produced  is  many  times  the  number  of  suspected  cases  of  winter- 
ing-over, so  that  even  allowing  for  a  lack  of  infection  in  some  instances, 
dying  out  of  the  mycelium  in  winter,  and  so  forth,  there  still  remain  several 
times  the  number  of  plantations  or  parts  of  plantations  required  to  ex- 
plain the  observed  outbreaks  of  the  rust. 

In  this  connection  it  may  be  noted  that  the  climatic  conditions  of  the 
Niagara  Peninsula  are  extremely  mild  for  the  latitude;  the  autumn  is 
long  and  open:  in  the  last  two  years  roses  have  been  in  bloom  in  Novem- 
ber; the  temperature  in  winter  rarely  falls  below  — 12**F.,  and  there  is 
an  early  start  of  growth  in  the  spring.  Under  such  conditions  the  per- 
sistence of  the  rust  on  currant  foliage  until  late  in  the  fall,  and  its  ready 
occurrence  on  the  secondary  foliage,  is  not  a  matter  of  wonder.  In  addi- 
tion the  buds  are  advanced  in  this  mild  fall  weather  far  beyond  the  stage 
at  which  they  usually  go  into  the  winter  in  other  localities.  Perhaps 
the  less  severe  winters  might  also  permit  the  mycelium  to  remain  alive  in 
infected  tissues  in  a  manner  that  would  be  impossible  in  colder  localities. 


20  Phytopathology  [Vol.  7 

2.  aqrbbment  op  hypothesis  with  analogous  cases 

The  view  that  the  mycelium  of  the  fungus  might  successfully  pass  the 
winter  in  currant  tissue  is  open  to  no  a  priori  objection.  What  is  the 
constant  habit  of  the  fungus  in  the  pine  might  well  become  a  temporary 
or  occasional  happening  on  the  other  host.  In  this  connection  it  is  scarcely 
nece88ar>'  to  point  out  the  known  habits  of  other  rusts  under  like  circum- 
stances, but  the  recent  work  of  Meinecke  (4)  on  Peridermium  harknessti 
has  a  peculiar  interest  here.  In  summarizing  this  work  he  says,  ''In  Cal- 
ifornia Peridermium  harknesm  and  Cr&nartium  Qiiercuum  are  to  a  high 
degree  independent  of  each  other;"  and  again,  **Cronartium  Quereuum 
over-winters  on  Quercus  agrifolia;  new  urediniospores  form  in  spring 
around  the  old,  dead  sori  on  old,  living  leaves,  and  infect  the  young  leaves." 
He  believes  that  since  the  crop  of  new  spores  is  formed  around  the  old 
dead  spots,  that  therefore  the  myceliimi  must  over-winter  in  the  leaf 
tissue.  The  same  over-wintering  of  the  myceliimi  has  l>een  found  by 
Mains  (2)  to  take  place  in  Coleosporium  SolidaginiSy  the  perfect  form  of 
Peridermium  acicolum.  In  this  case  the  pustules  of  the  fungus  were 
found  to  arise  in  spring  in  the  rosette  leaves  of  the  Solidago  host,  in  which 
the  myceliimi  had  apparently  over-wintered.  He  was  able  to  prove  this 
point  by  sectioning  the  leaves,  and  finding  therein  the  rust  hyphae  in 
limited  areas. 

3   AND  4.      APPEARANCE  OF  CURRANT  STAGE   WHERE    PINE   INFECTIONS 

DO   NOT  OCCUR 

(hi'ing  to  the  suspicions  that  arose  in  1915  concerning  the  possibiUty 
of  over-wintering  on  the  currant,  a  careful  inspection  was  planned  for 
lOIt),  in  onler  to  <letennine  whether  ca^es  of  early  infection  could  be 
found,  which  were  either  so  far  away  from  pines  as  to  preclude  the  pos- 
sibility of  pine  infection,  or  which  were*  close  only  to  pines  of  small  siie, 
whosi*  fn»<Miom  from  disease  (*ould  Ih»  al>solutely  establLnhed.  In  general 
there  arc  nuvh  nuinlM^rs  of  large  pines  scattered  over  the  whole  of  the 
Niagara  Pcininsula  that,  even  should  cas<»s  suspi(*ious  of  over-wintering 
Im*  found  to  occur  on  curnints,  the  n(*arness  of  the  other  host  would  ren- 
der thcw»  c:l*m*s  valueless  from  this  |Kiint  of  view.  In  two  areas,  how- 
ever, the  pin<»s  were  so  few  in  nmiiUT  that  an  early  ap|H»arance  of  the 
curniiit  ^tag(*  in  them  would  Im*  difficult  to  c^xplain  on  the  gnumd  of  pine 
infection. 

One  «if  thi'H*  areiu«  (comprises  that  part  of  (irantham  and  Niagara  town- 
ships included  within  the  d(»tted  line  on  the  map  (fig.  1),  which  it  will  be 
nf>ted  also  n^f^ords  the  (K)sition  f»f  all  |>ine  and  currant  plantations.  In 
191')  the  rust  in  this  area  did  not  start  inmi  a  |)articular  (*enter  or  centers 


1917]  McCvbbin:  White  Pine  Busteb  Rost 


I     -3 


I.  i 
is  -8 


22  Phytopathology  [Vol.  7 

and  spread  outward  therefrom,  but  it  appeared  simultaneously  and  ir- 
regularly over  the  whole  district,  totally  without  reference  to  the  few 
pines  to  be  found  there.  In  1916  the  very  same  irregular  occurrence  was 
noted.  Ibccept  in  the  Secord  case  hereinafter  mentioned,  there  were 
nowhere  any  signs  which  would  indicate  pine  infection;  the  infection  areas 
in  the  plantations  of  currants  were  usually  few,  often  only  one  or  two;  in 
no  case  was  early  infection  general  over  a  munber  of  adjacent  plantations, 
or  even  plentiful  in  one;  and  in  most  cases  the  only  pines  that  could  be 
suspected  were  more  or  less  surrounded  by  disease-free  currants. 

Of  the  twenty-nine  cases  of  currant  rust  (plantations)  found  in  the 
area  indicated,  sixteen  were  so  situated  as  to  be  regarded  with  strong 
suspicion.  Eight  of  the  sixteen  are  over  a^nile  distant  from  any  pine 
which  could  possibly  be  a  source  of  infection,  and  in  all  the  twenty-nine, 
except  in  the  Secord  case  noted  below,  the  rust  started  without  any  ap- 
parent reference  to  the  pines  in  the  neighborhood.  Eleven  of  the  twenty- 
nine  cases  originated  on  cither  one  or  two  bushes  in  a  plantation,  and  in 
all  of  these  eleven  the  primary  source  could  still  be  distinguished  on  the 
early  leaves  of  the  shoot.  In  sixteen  other  cases  of  the  twenty-nine  the 
origin  frohi  a  similar  small  beginning  was  evident,  but  owing  to  lack  of 
certainty  in  these  cases  they  are  not  included  as  evidence. 

Three  of  the  cases  occurring  in  this  area  deserve  special  mention  on 
account  of  their  typical  character,  and  because  of  the  strong  evidence 
they  bring  on  the  question. 

\o.  /,  Lot  17 y  Con,  5,  Grantham,  In  this  plantation  there  were  present 
on  July  6,  two  Imdly  diseased  bushes,  on  both  of  which  the  early  infec- 
tion had  started  on  the  second  leaf  of  the  shoot  and  had  spread  from 
there  over  the  rest  of  the  bush  and  to  the  adjoinitig  bushes  only.  There 
are  about  twenty  young  pines  four  hundred  feet  from  these  currants^ 
but  they  have  been  examined  several  times  in  1915  and  in  1916,  and  are 
all  entirely  free  from  the  disease.  Aside  from  these  the  nearest  pinee 
are  over  a  mile  distant  with  disease-free  currants  intervening. 

So.  2,  Lot  f).  Con,  S,  Grantham.  Here  are  four  old  black-currant  plants 
in  a  H*)mewluit  neglected  garden.  On  July  6  two  leaves  on  one  of  them 
had  very  old  infection  spot«,  while  around  these  on  the  bush  secondary 
unHlincKfnwtules  were  present.  The  other  bushes  were  absolutely  free 
fn)ni  the  ruj<t.  As  may  l)e  MH»n  by  reference  to  the  map,  there  are  three 
lots  of  pines  southeast  of  thus  place,  and  one  northeast.  All  these  are 
young  pines  and  are  fn»e  fn>m  any  signs  of  the  l)li.ster  rust.  This  disposes 
of  all  the  white  pines  for  nearly  two  miles  in  every  direction  except  one 
forty-yi»anM>ld  tree  in  I>ot  KM,  Niagara  Tp.,  which  is  one  and  a  fourth 
milc*s  distant. 


1917]  McCubbin:  White  Pine  Blistek  Rust  23 

No,  S,  Lot  S6y  Niagara  Tp,  The  map  shows  the  infected  plantation 
to  be  over  a  mile  from  any  pines  whatever.  It  is  moreover  in  the  center 
of  a  currant  area  of  which  it  alone  is  rusted.  On  July  15,  the  disease  was 
found  at  one  end  of  this  plantation  and  the  outbreak  was  traceable  to 
several  very  old  spots  on  early  leaves. 

In  the  second  of  the  two  areas  mentioned,  which  includes  the  town- 
ships of  Willoughby,  Crowland  and  Bertie,  in  Welland  Coxmty,  the  con- 
ditions are  exactly  the  same  as  have  just  been  outUned  for  the  Grantham- 
Niagara  district.  The  1916  infection  is  irregularly  scattered  over  the 
whole  territory  without  any  reference  to  the  pines.  Out  of  185  currant 
plantations  examined  here  seventeen  were  foimd  to  be  diseased,  of  which 
fourteen  were  suspected  to  be  cases  of  wintering  over.  In  four  of  the 
cases  the  currant  rust  was  found  from  one  to  two  miles  from  the  nearest 
pines,  and  even  then  these  pines  were  not  \mder  suspicion,  being  either 
themselves  far  from  a  source  of  infection  from  currants,  or  else  having 
disease-free  currants  near  them. 

Although  the  evidence  adduced  has  been  confined  to  the  rust  outbreaks 
in  these  limited  and  favorable  districts,  it  must  be  understood  that  the 
same  conditions  prevail  in  other  parts  of  the  peninsula,  and  it  is  only  the 
near  presence  of  so  many  pines  in  all  these  districts  which  precludes  add- 
ing a  large  number  of  other  cases  of  a  like  suspicious  nature.  Unless 
either  the  aeciospores  or  the  uredinospores  are  carried  by  the  wind  to  much 
greater  distances  than  we  are  accustomed  to  think,  or  than  our  limited 
experiences  would  indicate,  the  occiUTence  of  currant  rust  in  this  area 
in  1916  is  very  puzzling  on  any  other  hypothesis  than  that  of  wintering 
over  on  the  currant. 

In  addition  to  the  above  there  is  another  line  of  evidence  which  has  a 
direct  bearing  on  the  problem  of  the  origin  of  the  yearly  rust  outbreak 
in  the  Grantham-Niagara  area  already  mentioned.  This  evidence  is 
derived  from  careful  examinations  made  of  cases  in  the  district  where 
young  pines  and  black  currants  are  growing  in  close  proximity,  and  of 
these  the  most  outstanding  instance  was  on  Lot  13,  Con.  3,  Grantham, 
which  for  convenience  of  reference  is  called  the  Secord  case. 

On  the  Pecord  farm  there  was  a  row  of  sixteen  yoimg  white  pines  planted 
along  the  western  boundary.  These  pines  were  obtained  from  a  native 
wood-lot  in  the  neighborhood,  and  were  planted  out  in  1910.  Rimning 
from  a  lane  in  the  middle  of  the  farm  to  this  row  of  pines  are  175  large 
black  currant  bushes  in  five  rows.  On  the  eastern  side  of  the  lane,  and 
about  ninety  yards  farther  north,  is  a  small  nursery  plot  of  evergreens, 
among  which  were  included  about  150  young  white  pines,  planted  in 
1912,  and  obtained  from  the  Provincial  Forestry  plantation  in  Norfolk 
County,  where  they  had  been  grown  from  native  seed. 


24 


Phytopathology 


[Vol.  7 


Although  the  currants  on  this  farm  were  badly  rusted  in  1914  there 
was  no  sign  of  the  disease  on  either  lot  of  pines  that  year.  In  the  season 
of  1915  the  pines  were  all  examined  four  times  (May  5,  May  14,  June  14, 
August  9),  but  nothing  remotely  resembling  the  blister  rust  was  found. 
The  rust  appeared  again  on  the  currants  in  the  course  of  the  sununer, 
but  was  late  in  making  its  appearance,  and  possibly  came  in  from  else- 
where. Another  inspection  of  the  young  pines  was  made  very  early  in 
the  spring  of  1916,  with  the  same  result  as  before:  no  sign  of  the  disease 
could  lx»  seen. 

Owing  to  the  close  association  of  the  two  hosts,  and  the  known  occurrence 
of  the  currant  stage  for  at  least  the  two  preceding  years,  special  attention 
was  judged  to  \ye  necessary  in  this  case,  and  accordingly  a  further  inspec- 
tion was  made  on  June  6  and  7.  On  this  occasion  there  were  found  a 
large  number  of  discolored  swellings  which  were  undoubtedly  the  early 

TABLE  1 

Total  numittr  of  white  pint  blister  rujtt  swellings  found  June  6,  1916,  in  the  Secord 
nurnenj  and  fence  row  and  the  age  of  growth  on  which  they  occurred 


TKAR   or  OBOWTM 

NUBSBRT 

rSNCB    ROW 

TOTAL 

PBBCKMTAOB 

1015 

0 

V 

1 

0   5 

1914 

43 

M* 

127 

71.7 

1913 

39 

10 

49 

27.7 

191J 

0 

0 

0 

0 

Karli«»r 

0 

0 

0 

0 

*  Somewhat  dnuhtful.     A  pwelling  l)el()w  the  end  of  a  broken-off  terminal  branch. 

*  One  cif  thene  prcHlure<i  the  hliMterK  noted  above.     It  waa  located  at  the  upper 
end  of  the  interntnie  developed  in  1914. 


8tHg(*8  of  the  blister  rust,  and  which  had  developed  so  as  to  be  visible 
«inr<»  the  former  visit.  Only  one  case  of  the  blister  stage  was  found: 
A  .sinall  twig  near  the  ground  l)ore  five  small  blisters.  These  had  already 
shcMJ  their  sjxires.  but  were  still  readily  recognizable  by  the  slit-like  open- 
ings. miinHnts  of  the  |M*ri(iiuni,  and  by  a  few  remaining  spores.  The  pines 
were  niitiiitely  examined  over  ever>'  part  of  the  stems^  branches  and  twigs, 
and  all  the  swellings  collected  for  study,  after  which  the  trees  were  de- 
stn»viM|.  The  rollertion  of  swellings  was  then  carefully  gone  over  in  the 
lalH)ratory,  and  a  record  was  made  of  the  age  of  the  growth  on  which  they 
o<vurre<l.     Their  position  on  the  tree  is  given  in  tabular  form  below. 

Sinc<»  the  two  hosts  art»  here  so  closely  associated  that  the  currant  stage 
c<Hild  hardly  l>e  presiMit  without  causing  some  infection  on  the  pine,  we 
are  enahlcMi  to  fonn  from  this  table  some  conclusion  regarding  the  date 
of  the  first  apfx^arance  of  the  disea^*  in  this  particular  locality.     As  no 


1917]  McCubbin:  White  Pine  Blister  Rust  25 

pine  infections  have  been  found  on  any  growth  prior  to  and  including 
1912  it  seems  certain  that  there  was  no  currant  rust  here  before  1913  at 
least.  It  is,  of  course,  possible  that  sporidia  of  1913  might  have  infected 
twigs  of  1911  or  1912,  but  if  so  it  is  hard  to  believe  that  all  such  infections 
are  still  dormant  when  later  pine  infections  have  developed  regularly 
and  vigorously  on  the  same  trees.  This  seems  to  hint  at  the  absence  of 
the  currant  rust  here  in  1913,  but  this  part  of  the  subject  will  be  considered 
later. 

Since  the  currants  have  been  known  to  be  badly  rusted  in  1914,  1915, 
and  1916,  it  is  only  reasonable  to  suppose  that  plentiful  infections  have 
taken  place  in  each  of  these  years  on  pines  so  favorably  situated,  a  point 
which  is  well  borne  out  by  the  presence  of  such  large  numbers  of  them 
on  the  wood  of  1914.  These  must  obviously  have  arisen  after  the  wood 
was  formed,  and  are  therefore  leferable  to  the  rust  of  1914  or  1915.  The 
above  table,  however,  shows  an  entire  absence  of  infections  on  1915 
twigs  (save  for  one  very  doubtful  and  abnormal  case),  and  since  no  swell- 
ings or  other  indications  of  the  disease  were  seen  here  in  1915,  although 
the  pines  were  certainly  subject  to  infection  in  1914,  it  seems  fair  to  con- 
clude that  during  the  season  after  infection  the  fungus  produces  in  the 
twigs  no  symptoms  of  a  visible  nature. 

If  in  addition  to  this  year  of  dormancy  it  is  assumed  that  the  swell- 
ings formed  in  1916  will  reach  the  blister  stage  in  1917,  it  is  probable  that 
the  disease  in  pine  limbs  follows  a  four-year  cycle,  which  may  be  thus  sum- 
marized: first  year,  infection  in  late  siunmeror  fall;  second  year,  dormant 
period;  third  year,  swelling  and  discoloration,  with  possibly  pycnospores; 
fourth  year,  production  of  aecia. 

This  rule  of  development  is  not  to  be  regarded  as  invariable.  In  some 
cases  the  dormant  period  may  be  extended  considerably,  and  on  the 
other  hand  cases  are  known  where  blisters  have  been  formed  in  the  second 
year  after  infection  instead  of  the  third.  Under  ordinary  circumstances, 
however,  this  cycle  is  perhaps  generally  followed. 

We  may  therefore  consider  the  swellings  included  in  the  above  table 
as  having  originated  from  infections  of  either  1914,  or  both  1913  and  1914. 
Since  no  record  exists  of  the  presence  or  absence  of  the  rust  here  before 
1914,  we  are  unable  to  state  that  these  pines  were  not  exposed  to  infec- 
tion in  1913.  But  if  they  were  so  exposed  and  infections  resulted,  we 
are  compelled  to  give  an  explanation  of  the  sudden  development  into 
the  swelling  stage  of  infections  of  two  seasons,  simultaneously  in  the  spring 
of  1916.  If  currant  rust  was  present  in  1913  it  is  obvious  that  every  one 
of  a  large  number  of  infections  made  in  that  year  must  have  remained 
dormant  for  two  years,  while  on  the  self-same  trees  a  still  larger  number 
starting  in  1914  reached  the  same  stage  concurrently,  after  only  one 


26  Phytopathology  [Vol.  7 

year's  dormancy.  One  might  imagine  that  adverse  weather  conditionfl 
might  bring  about  such  a  pecuhar  varation  in  the  dormant  period,  but  it 
must  be  noted  that  during  the  spring  and  summer  of  1915  there  were 
collected  at  Fonthill,  some  fifteen  miles  away,  about  two  hundred  pine 
infections,  in  all  of  which  the  swelling  stage  in  both  old  and  incipient 
cankers  was  abundantly  active.  Aside  from  this  one  would  hardly  ex- 
pect all  these  cankers  to  be  affected  by  weather  conditions;  some  of  them 
might  be  retarded  but  others  more  favorably  situated  would  have  followed 
the  usual  course,  and  would  have  appeared  as  swellings  in  1915.  It  seems 
far  more  reasonable  to  regard  all  the  swellings  in  the  table  as  the  result 
of  a  single  year's  infection,  that  of  1914.  According  to  this  view  they 
have  all  followed  the  cycle  indicated  (with  the  exception  noted),  and  are 
due  to  produce  accia  in  1917.  It  would  follow  from  this,  that  the  cur- 
rant  rust  could  hardly  have  lx»en  present  on  these  currants  prior  to  1914, 
the  year  it  was  first  discovered  here. 

Since  the  Secord  fann,  (fig.  1,  -4),  is  ver>'  centrally  situated  in  the 
to\^aiship  of  drantham  and  in  the  heart  of  a  region  thickly  planted  with 
currants,  the  al)sence  of  currant  rust  here  is  strongly  indicative  of  its 
al)sence  in  the  surrounding  neighborhood.  Additional  evidence  on  this 
point  is  fiunished  by  four  other  cases  of  a  like  nature  in  the  same  district, 
where  pines  of  small  size  also  grew  side  by  side  with  black  currants. 

In  the  first  of  these,  (fig.  1,  B)^  a  large  currant  field  is  25  yards  distant 
from  a  number  of  young  native  pines,  on  which  no  signs  of  the  disease 
could  l)e  found  in  1915,  In  ()ctolx?r,  1916,  there  were  found  on  fourteen 
of  these  pines  thirty-eight  cases  of  the  blister  rust  swellings.  Of  these 
sixteen  were  on  the  growth  of  1913  and  twenty-two  on  that  of  1914. 
None  could  Ik?  found  on  growth  of  1915  and  nothing  was  present  on  any 
wood  prior  to  that  of  1913. 

In  the  w»cond  case  (fig.  1,  C)  there  were  two  young  pines  within  six 
fe<*t  of  the  black  currants.  In  1916  these  also  developed  swellings  for 
the  first  time;  of  the  five  seen  here  two  were  on  wood  of  1913  and  three 
on   that   of   1914. 

In  the  third  case  (fig.  1.  />),  the  few  young  pines  were  about  fifty  yards 
fn>m  a  short  n)w  of  black  currants.  The  one  case  of  pine  infection  which 
app<»are<l  here  for  the  first  time  in  1916  yunn  on  a  shoot  developed  in  1914. 

The  fourth  case  (fig.  1,  A'),  dis<'lose<l  only  two  pine  infections  on  a  doien 
young  trees  which  were  within  ten  feet  of  a  large  but  slightly  affected 
black  currant  plantation.  Ik>th  infections  wcn^  on  pine  shoots  of  1913 
growth.  There  is  some  a<lditional  evidence  here  in  the  fact  that  this 
n)W  of  pines  was  transplante<l  to  its  presi^nt  situation  in  the  spring  of 
1914  fn»ni  a  hollow  alM)Ut  four  hundred  yards  fnnii  these  currants.  Since 
there  were  no  other  currants  within  a  quarter  of  a  mile  of  this  hoUow, 


1917]  McCubbin:  White  Pine  Blistek  Rust  27 

there  is  good  reason  to  believe  that  the  pines  received  their  infection  after 
they  were  transplanted,  that  is,  in  1914. 

In  all  the  four  cases  just  referred  to  the  adjacent  currants  are  known 
to  have  been  diseased  in  1914.  Likewise  the  pines  were  in  every  case 
minutely  examined  in  1915,  so  that  their  freedom  from  disease  until  the 
spring  of  1916  is  well  established.  Since  in  every  one  of  the  blister  can- 
kers found  in  these  foiu'  cases  the  disease  has  occurred  only  on  wood  of 
1913  or  1914,  and  none  have  been  visible  till  ihe  spring  of  1916,  they  agree 
in  every  way  with  the  evidence  obtained  from  the  Secord  case,  and  to- 
gether with  it  give  a  very  strong  support  to  the  view  that  the  ciurant 
rust  was  not  present  in  the  Niagara-Grantham  region  before  1914. 

The  bearing  of  this  aonclusion  on  the  question  of  wintering  over  is 
obvious.  If  the  rust  did  not  appear  in  this  district  until  1914,  then  ac- 
cording to  the  probable  life-cycle  of  the  fungus  no  pine  infections  could 
reach  the  blister  stage  and  start  new  currant  infection  before  1917.  It 
follows  therefore  that  the  currant  rust  of  1915  and  1916  in  the  area  imder 
consideration  must  be  due  either  to  spores  carried  for  long  distances  by 
the  wind  or  to  a  wintering  of  the  fungus  on  the  currants  themselves. 
Since  this  area  is  about  ten  miles  long  by  five  miles  wide,  and  is  distant 
from  the  nearest  area  of  infection  (the  Fonthill  district)  from  ten  to  six- 
teen miles,  any  attempt  to  attribute  all  these  rust  outbreaks  to  wind- 
blown spores  is  full  of  diflSculty.  Aside  from  this  there  remains  only  the 
wintering  of  the  fungus  on  the  ciu'rants  as  an  explanation. 

Objection  may  be  made  to  the  above  reasoning  on  the  ground  that  in 
some  instances  aecia  may  be  produced  the  second  spring  after  infection 
instead  of  the  third.  It  is  probable  that  such  cases  are  rare.  The  single 
instance  of  this  sort  that  was  met  with  in  the  Secord  case  was  the  only 
one  out  of  223  blister  cankers  collected  in  these  two  townships  in  1916. 
The  small  branch  on  which  it  was  found  was  protected  by  high  grass, 
and  had  the  puffed,  swollen  appearance  which  normally  occurs  when  a 
small  limb  is  stimulated  by  contact  with  the  moist  earth.  It  was  evidently 
an  abnormal  case,  and  probably  had  undergone  a  forced  development 
by  reason  of  its  peculiar  conditions.  The  writer  is  of  the  opinion  that 
such  abnormalities  would  rarely  occur  in  large  trees,  and  as  for  the  small 
pines,  practically  all  of  these  in  the  two  townships  have  been  subjected 
to  such  a  scrutiny  that  the  possibility  of  their  playing  a  part  in  the  yearly 
outbreak  is  utterly  out  of  the  question.  This  is  especially  apparent  when 
the  extent  of  the  early  occurrence  of  the  currant  stage  is  taken  into  con- 
sideration along  with  the  observed  rate  of  spread  from  the  infection  started 
at  the  Secord  farm  by  the  abnormal  blisters  just  mentioned.  In  this 
case  the  rust  began  about  June  1,  at  the  ends  of  the  five  rows  of  black 
currants.    By  July  6,  it  had  progressed  down  the  rows  for  a  distance  of 


28  Phytopathology  [Vol.  7 

only  two  hundred  feet,  and  two  adjoining  plantations  distant  two  hun- 
dred and  three  hundred  yards  respectively/  were  still  free  from  any  sign 
of  infection.  By  August  21,  there  was  only  a  slight  infection  on  these 
adjacent  plantations.  It  is  almost  impossible  to  think  that  one  small 
infection  of  this  sort,  or  even  a  number  of  them,  could  have  started  such 
a  widespread  infection  on  currants  as  our  survey  disclosed. 

Moreover,  while  an  objection  of  this  nature  might  be  vaUd  for  the 
rust  epidemic  of  1916,  it  could  hardly  apply  to  that  of  1915  which  was  of 
the  same  extent  and  in  the  same  area.  Assuming  that  the  rust  entered 
this  district  in  1914  any  explanation  of  the  succeeding  year's  outbreak 
on  the  basis  of  pine  infection  would  require  the  production  of  the  blister 
stage  in  the  spring  of  1915,  from  a  blister  canker  started  by  infection  dur- 
ing the  previous  autumn.  Even  admitting  the  possibility  of  such  pre- 
cocious development,  the  blisters  formed  in  this  way  must  either  have 
been  numerous  and  widespread,  or  the  spores  from  one  or  a  few  of  them 
must  have  been  carried  from  five  to  ten  miles.  In  the  first  case  our  care- 
ful examination  of  young  pines  must  have  disclosed  some  of  them,  at 
least ;  and  in  the  second  case  the  general  and  irregular  occurrence  of  snuill 
outbreaks  without  any  recognizable  center  of  infection,  together  with 
the  known  behavior  of  the  already  mentioned  outbreak  of  this  nature 
on  the  Secord  farm,  are  quite  against  any  such  explanation. 

5.    RECURRENCE  ON   SAME   INDIVIDUAL 

The  hypothesis  advanced  al)ove  is  capable  of  being  tested  to  some  ex- 
tent by  field  ol)8cr\'ations.  If  the  rust  winters  in  buds  forced  into  late 
growth  by  premature  defoliation,  then  it  should  be  possible  toestablish 
a  connection  l)etween  suspicious  early  outbreaks  of  the  rust  and  the 
plants  or  small  areas  which  were  defoliated  during  the  preceding  summer; 
if  these  areas  showing  force<l  growth  were  marked  in  the  fall  and  rust 
appeared  in  them  in  spring  in  a  largcT  percentage  of  cases  than  in  the 
or<linar>'  parts  of  the  field,  the  case  for  over-wintering  would  be  very 
stmng  indwMl.  Such  field  work  would  necessarily  have  to  be  done  in  a 
district  when»  the  n^sults  would  not  be  interfered  with  by  the  presence 
of  too  many  pines. 

rnfortunately  no  «yHtematic  effort  has  yet  l)een  made  along  this  line. 
The  Humll  amount  of  €»vi(leiire  now  in  hand  conies  from  three  plantations 
which  were  niarkecl  as  defoliated  in  1915.  Out  of  the  three,  two  were 
subject  to  early  outbreaks  of  the  rust  in  1910.  while  the  thin!  was  free. 
In  U)th  of  the  two  cjises  the  infection  wjis  small  and  startec!  from  one  or 
two  renters  within  the  defoliatcNl  portion.  \  |)erhaps  more  significant 
case  came  up  in  the  field  work  of  one  of  the  ins|K>ctors.     In  one  large 


1917]  McCubbin:  White  Pine  Blister  Rust  29 

black  currant  plantation  the  inspector  who  covered  the  ground  in  1915 
reported  only  four  bushes,  adjacent  in  a  row,  as  badly  rusted,  with  but 
slight  infection  elsewhere  on  adjoining  plants.  These  four  bushes  were 
seen  at  that  time  by  the  owner,  and  when  the  inspector  of  1916  called  here, 
the  owner  told  him  where  to  find  these  bushes,  which  were  on  the  side 
of  the  plantation  opposite  a  small  tree.  The  only  case  of  rust  which 
could  be  found  in  this  plantation  was  on  one  of  the  four  plants  mentioned. 
It  is  conceivable  that  spores  blown  from  some  other  place  might  start 
an  infection  in  this  one  spot,  and  there  only,  in  two  successive  years, 
but  it  is  so  utterly  improbable  that  one  can  scarcely  avoid  turning  to  the 
wintering-over  hypothesis  for  an  adequate  explanation  of  the  case. 

6.   RUST  ON  transplants  IN  A  RU8T-PREB  DISTRICT 

In  a  former  article  (3)  mention  has  been  made  of  a  rust  outbreak  which 
occurred  in  a  small  plot  of  black  currants  set  out  in  the  spring  of  1915 
to  test  for  hibernation.  The  one  hundred  currant  bushes  used  were  all 
badly  rusted  in  1914.  They  were  divided  into  five  lots,  of  which  two 
were  well  sprayed  with  lime-sulphur,  two  were  left  unsprayed,  and  one 
was  exposed  to  infection  from  rusted  currant  leaves  wintered  out-of-doors 
and  suspended  among  the  foliage  in  loose  wire  baskets.  A  locality  was 
chosen  for  the  experiment  far  away  from  any  known  rust  area;  this  dis- 
trict had  few  pines  and  the  freedom  from  rust  of  the  few  existing  currants 
was  ascertained  during  the  fall  of  1914. 

The  one  case  of  rust  which  developed  on  these  plants  was  on  one  of  the 
sprayed  plots.  At  the  time  of  examination,  October  18,  it  was  still  of 
very  small  extent,  involving  only  one  shoot  of  a  single  plant.  There  was 
a  small  original  rust  spot  surrounded  by  about  twenty  others  of  more 
recent  date. 

Owing  to  the  limited  extent  of  the  rust  here  so  late  in  the  season  there 
was  some  hesitation  in  attributing  it  to  a  wintering  of  the  fungus,  and 
every  other  possible  source  of  infection  was  given  due  consideration. 
The  only  one  of  these  possible  sources  that  had  any  degree  of  probability 
was  the  carrying  of  aeciospores  to  this  place  in  an  inspection  visit  made  on 
May  24.  At  this  date  no  currant  rust  had  been  met  with  but  some  inocula- 
tions with  the  aeciospores  6ad  been  made  in  the  laboratory  on  May  20. 
The  writer  did  not  do  this  work  himself  but  was  in  the  room  at  the  time, 
and  a  few  air-borne  spores  might  have  adhered  to  his  clothing  and  have 
been  thus  carried  to  the  field  in  question  four  days  later.  Improbable 
as  this  suggestion  may  seem,  it  is  the  only  explanation  on  the  basis  Qf 

accidental  infection  which  seems  to  be  worth  consideration, 


30  Phytopathology  [Vol.  7 

On  the  other  hand  the  wintering  of  the  fungus  on  the  curranta  them- 
selves readily  explains  the  case.  The  fact  that  the  plants  were  well 
sprayed  in  spring  is  in  perfect  harmony  with  the  hypothesis  advanced. 
Even  the  late  appearance  and  small  spread  of  the  infection,  which  would 
appear  to  be  incompatible  with  wintering-over,  need  present  no  difficulty; 
it  is  well  known  that  while  Puccinia  graminis  may  live  independently 
of  the  barberry  for  indefinite  periods,  yet  by  undergoing  its  proper  stage 
on  this  host  its  virulency  on  cereal  hosts  is  much  increased.  It  should 
not  l)e  too  much  to  expect,  then,  that  in  the  case  of  Cronariium  ribicola 
the  second  successive  seasonal  generation  on  the  currant  should  lack 
somewhat  of  the  vigor  it  would  possess  after  coming  fresh  from  the  pine. 
The  results  of  the  sur\'ey  work  in  the  Niagara  Peninsula  seem  to  hint 
at  a  confirmation  of  this  view.  A  great  many  of  the  cases  of  currant 
rust  observed  here  during  the  last  two  years  have  been  in  the  type  in- 
dicated :  an  old  but  very  feeble  rust  center,  which  by  the  end  of  the  sum- 
mer had  involved  only  a  single  bush,  or  at  most  a  few  adjacent  bushes. 
Other  explanations  of  this  seeming  lack  of  vigor  are  no  doubt  possible, 
but  such  a  decadence  is  quite  compatible  with  a  hibernation  hypothesis. 

In  concluding  this  discussion  it  is  clearly  recognized  that  the  evidence 
submitted  is  inadequate  to  establish  the  point  under  consideration,  but 
on  the  other  hand  it  is  considere<l  that  enough  evidence  has  been  adduced 
to  warrant  a  strong  suspicion  of  currant  hibernation,  and  this  suspicion 
holds  even  though  the  hypothesis  tentatively  put  forward  should  prove 
to  l>e  untenable  in  the  light  of  later  investigation.  In  any  case  the  evi- 
dence obtauiod  8er\'es  to  narrow  the  field  of  inquiry  to  a  great  extent; 
for  the  conditions  outlined  above  are  such  that  the  question  of  hil>ernation 
clearly  hinges  on  the  distance  aeciospores  or  uredinospores  can  l)e  car- 
ried by  the  wind;  if  only  for  a  mile  or  two,  then  wintering  on  the  currant 
has  almost  certainly  taken  place  in  the  area  under  consideration;  if  on 
the  other  hand  the  spores  are  Iwrne  eight  or  ten  miles  or  farther,  another 
explanation  of  the  situation  in  this  district  l>ecomes  easily  possible,  al- 
though the  question  of  hibeniation  is  not  even  then  altogether  disposed 
of.  In  the  al)sence  of  definite  infonnation  concerning  si>ore  dispersal 
the  cjuestion  must  remain  o|H»n  until  a  l>ody  of  trustworthy  evidence  can 
Ih»  acnmuilated  on  this  |)oint,  or  until  more  direct  evidence  is  available 
on  other  phases  of  the  subject. 

Dominion  Fikld  Lahoratory  of  Plant  Pathoukjy 
St.  Catharines,  Ontario 


1917]  McCubbin:  White  Pine  Blister  Rust  31 

BIBLIOGRAPHY 

(1)  HowiTT,  J.  E.,  and  McCubbin,  W.  A.    An  outbreak  of  white  pine  blister  rust 

in  Ontario.    Phytopath.  6:  182-185.    1916. 

(2)  Mains,   E.   B.    The  wintering  of  Coleosporium  Solidaginis.    Phytopath.  6: 

371.     1916. 

(3)  McCubbin,  W.  A.    Notes  on  white  pine  blister  rust.    Rept.  Dominion  Bota- 

nist (Ottawa,  Canada)  1915-16: 

(4)  Meinecke,  E.  p.    Peridermium  harknessii  and  Cronartium  Quercuum.    Phy- 

topath. 6:  225-240.     1916. 
(6)  Spauldino,  Perlet.    The  blister  rust  of  white  j}ine.    U.  S.  D.  A.,  Bur.  PI. 

Ind.  Bull.  206:  1911. 
(5a)  The  present  status  of  the  white  pine  blister  rust.     U.  S.  Bur.  Plant  Ind. 

Circ.  129:  15.     1913. 

(6)  Notes  on  the  white  pine  blister  rust.    Phytopath.  4:  41.    1914. 

(7)  New  facts  concerning  the  white  pine  blister  rust.     U.  S.  D.  A.,  Bui.  116: 

4-5.     1914. 

(8)  Stewart,  F.  C.    An  outbreak  of  European  currant  rust.    New  York  (Geneva) 

Agr.  Exp.  Sta.,  Tech.  Bui.  2.     1906. 

(9)  Stewart,  F.  C,  and  Rankin,  W.  H.    Can  Cronartium  ribicola  over-winter  on 

the  currant?    Phytopath.,  4:  43.     1914. 


THE  INJURIOUS  EFFECTS  OF  TARVIA  FUMES  ON 

VEGETATION 

A.   H.   Chivers 

The  following  article  contains  a  brief  description  of  the  destructive 
efToct  of  tar  smoke  on  plants  which  the  writer  had  occasion  to  study 
during  the  sununer  of  1914,  together  with  a  brief  account  of  experiments 
carried  on  since  that  time  in  the  laboratory,  and  under  controlled  con- 
ditions. 

The  tar  compound  which  was  in  use  for  building  purposes,  and  which 
seriously  affected  the  neighboring  vegetation,  is  sold  under  the  trade 
name,  tarvia.  For  melting  the  compound  a  single  kettle  was  set  up 
alK)Ut  sixty  feet  distant  from  the  nearest  corner,  and  three  hundred  feet 
distant  from  the  farthest  corner,  of  a  garden  which  covered  an  area  roughly 
a  hundre<l  and  eighty  feet  square,  and  which  contained  both  ornamental 
and  cn)p  plants. 

A  strong  and  constant  wind  carried  the  fumes  over  the  garden  for  about 
four  hours  on  the  afternoon  of  August  10  and  throughout  the  forenoon 
of  August  11,  during  which  tune  the  leaves  and  stems  of  the  planta  l)e- 
came  coated  with  a  sulwtance  of  a  greasy  nature. 

The  sulisetjuent  destruction  of  the  plants  was  ver>'  rapid.  The  leaves 
scHin  curled  and  shrivelled,  dried  out  and  fell.  At  least  twenty  species 
and  numy  varieties  were  affect €»(!.  Poppies,  P,  soinnifirum  Linn.,  P,  rhoeas 
Linn.,  P,  orieuUile  Linn.,  candytuft,  Ilxrin  amara  Linn.;  marigolds,  Caleri- 
dula  officinaliH  Linn.;  azaleas,  Azalea  vinami  Linn.;  sunflowers,  Helian- 
thuM  anfiuuM  Linn.;  strawln^rries,  Fragaria  in  varieties,  and  squashes, 
i^iCurhiUi  jH}H)  Linn.,  and  (\  maxima  Duchesn(»,  were  killed.  Pae<mies, 
Parouia  in  varieties,  were  killed  to  the  surface  ui  the  soil.  Roses,  Rom 
in  varieties:  hoiiey.^uckles,  Ltnicrra  Uirtarica  in  varietit*s;  currants, 
Wi7x\K  in  vari«'ti<\s;  ra.*<plM'rrieH.  black  ra.*<pl Harries  and  blacklnmes,  Kubus 
in  varii'tirs,  were  dcfoliatet),  uimI  in  son:e  instances  were  killed.  Pota- 
toes. Snlauum  tulMroftum  Linn.,  which  occujMed  the  greater  part  of  the 
garden,  were  stunt€»<l  and  the  yield  was  greatly  reduced.  All  perennials 
showed  the  effects  of  the  injury  in  the  following  season's  growth. 

IIHIKF   Sl'MMARY    OF   MTKIiATlKE 

( )bs«Tvations  on  the  effect  of  vaiK)r  an<l  dust  fnmi  tarred  roads,  and 
smoke  from  melting  tar  on  neighlK)ring  vegetation,  have  led  to  extensive 


1917]  Chivers:  Eppbcts  op  Tarvia  Fumes  33 

investigation  of  many  tar  compounds,  and  it  has  been  found  that  while 
these  compounds  vary  widely,  the  smoke  and  fumes  from  these  are  in 
general  injurious  to  plants. 

Gatin^  investigated  different  substances  used  for  the  surface  treat- 
ment of  roads  and  his  results  tended  to  show  that  many  trees,  shrubs, 
garden  plants  and  flowers  suffered  injury  from  the  fumes  given  off  by  the 
tar,  and  also  from  the  dust  arisinjg  from  the  treated  roads.  The  injury 
seemed  to  be  proportional  to  the  distance  from  the  road,  the  amount 
of  phenol  in  the  compoimd,  and  the  isolation  of  the  plants.  The  effect 
was  shown  in  the  fading  of  the  leaves  which  were  spotted  and  blackened. 
The  cells  were  plasmolyzed  and  the  chlorophyll  disappeared.  Marked 
differences  in  resistance  to  injmry  on  the  part  of  some  plants  were  noted. 

Gatin  and  Fluteaux^  found  as  a  result  of  studies  on  leaves  and  branches 
of  catalpa  and  locust  that  plants  which  have  been  submitted  diu'ing  the 
season  to  the  dust  from  tarred  roads  had  become  considerably  modified 
in  respect  to  anatomical  structure. 

Mirande^  made  a  study  of  the  influence  of  the  tarring  of  roads  on  plants, 
and  concluded  that  the  injmy  was  done  by  vapors  given  off  in  consider- 
able abundance  diu-ing  dry,  hot  weather.  He  stated  that  if  trees  and 
ornamental  plants  in  cities  are  to  be  preserved  the  use  of  tar  on  roads 
should  be  made  with  care.  The  same  author*  investigated  the  effects 
on  plants  of  a  number  of  commercial  products  such  as  Carbonyle,  Car- 
bolineum  and  Carboneine,  all  of  which  contained  creosote,  and  a  nimiber 
of  which  were  used  as  insecticides.  They  were  more  or  less  injurious, 
causing  the  destruction  of  the  green  cells.  He  urged  care  in  their 
application. 

Griffon,*  as  a  result  of  laboratory  work  covering  three  seasons,  confirmed 
the  conclusions  of  Mirande  regarding  the  injurious  nature  of  gases  given 
off  from  tar  when  used  in  coating  roads.    From  extensive  observations 

^  Gatin^  C.  L.  The  efifects  of  tarring  roads  on  the  growth  of  trees  in  the  Bois  de 
Boulogn.  Compt.  Rend.  Acad.  Sci.    Paris.    168:  202-204.    1911. 

The  experimental  reproduction  of  the  injury  to  plants  by  the  vapors  and 

dust  arising  from  tarred  roads.  Compt.  Rend.  Acad.  Sci.  Paris.  168:  688^90. 
1911. 

The  tarring  of  roads  and  its  effect  on  the  neighboring  vegetation.    Ann. 

Sci.  Nat.  Hot.,  ser.  9,  16:  165-252.    1912. 

'  Gatin,  C.  L.  and  Fluteaux.  Anatomical  modifications  produced  on  plants 
by  dust  from  tarred  roads.    Compt.  Rend.  Acad.  Sci.    Paris.  168:  1020-1021.    1911. 

*  Mirande,  M.  The  effect  of  tarring  roads  on  plants.  Compt.  Rend.  Acad. 
Sci.    Paris.    161:949-952.    1910. 

*  Mirande,  M.  The  effect  on  plants  of  certain  substances  extracted  from  coal 
tar.    Compt.  Rend.  Acad.  Sci.    Paris.    162:  204-206.    1911. 

*  Griffon,  £.  The  influence  of  tarring  roads  on  neighboring  vegetation.  Compt. 
Rend.  Acad.  Sci.    Paris.    161:  1070-1073.    1910. 


34  Phytopathology  [Voi^  7 

he  concluded  that  the  probable  injury  to  vegetation  in  the  open  coun- 
try would  be  small. 

CMaussen*  exposed  plants  to  vapors  of  several  coniniercial  tars,  and 
found  that  the  various  kinds  of  tar  sold  for  building  highways  differed 
widely  as  to  their  effects  on  plants.  The  nature  and  extent  of  the  in- 
jury' were  closely  related  to  the  concentration,  thus  depending  on  vola- 
tility and  temperature,  and  that  species  of  plants  differed  widely  as  to 
their  susceptibility  to  the  vapors.  Certain  recommendations  were  made 
in  respect  to  the  proper  handling  of  such  products. 

Gabnay'  gave  a  brief  account  of  the  injury  to  trees  by  tar  used  on  the 
trunks  as  protection  against  the  ascent  of  caterpillars,  which  involved 
not  only  the  cambium  but  also  the  sap  wood,  and  extended  beyond  the 
limits  of  the  tarred  areas.  The  injury  was  ascril)ed  to  the  exclusion  of 
air  and  the  action  of  acids  and  salts. 

Ewert'  investigated  the  injiu^  to  vegetation  by  smoke-borne  products, 
and  reported  a  peculiar  lacquered  appearance  on  the  upper  surface  of 
leaves  of  a  number  of  economic  plants,  frecjuent  rolling  and  crumbling 
of  the  laminae,  and  discoloration  over  part  or  all  of  the  surface.  Fruits 
and  garden  produce  in  such  neighborhoods  showed  the  effects.  Controlled 
experiments  showed  that  injury  depended  not  alone  upon  the  amount 
of  material  present  in  the  atmosphere,  but  also  ujwn  the  heat,  dryness 
and  isolation. 

A  cas<*  most  similar  to  the  one  under  discussion  is  recorded  by  Moore* 
as  having  occurred  at  Woods  Hole,  Massachusetts,  when  a  collection  of 
valuable  roses  was  seriously  damaged  by  smoke  which  resulted  from  the 
burning  of  a  tar  and  gravel  roof  in  the  vicinity  of  the  garden.  The  effect 
of  the  smoke  began  to  be  noticeable  during  the  third  day  of  the  fire,  and 
was  indicated  not  only  externally  by  the  falling  of  the  leaves  and  the 
scarring  and  marking  of  the  young  and  tender  stems,  but  also  internally 
where  large  areas  of  growing  tissue  died  and  the  contents  of  the  cells 
were  shrunken  and  di**torte<l,  the  green  coloring  matter  luiving  been 
completely  <lis<irgunize<l.  All  plants  were  affected,  some  were  killiHl 
outright,  and  others  so  weakened  that  they  l)i»ciune  much  more  susceptible 
to  the  attack  of  fungous  db<ea«es. 

•  ClaiiHHon,  r.  TUv  infliienr<>  of  tar,  particularly  that  of  tarred  strccta  upon 
vegetation.     Arl».  KaiM.  Hiol    An«t.  I^nd.  u.  For«tw.  8:  403-.')l4.     1913. 

'  Cialinay,  F.  von.  The  patholoxical  action  of  tar  on  plants.  (Vntbl.  Omam. 
ForMtw.  S9:  497  .VM.     1913. 

•  Kwert,  H.  Injury  to  vegetation  by  coal  tar  and  other  vapors,  and  protection 
therefrom.     Zeitiirhr    Pflani«»nk    U:  257  273,  321  34().     1914. 

•  Moore.  (;.  T.     Ho»t!J«  vii.  Kailroadw.     Kho<!ora  5:  93-96      1903. 


iai7]  CnrvERs:  Effects  of  Tarvia  Fumes  35 

The  very  complete  bibliography  of  McClelland^  also  should  be  con- 
sulted in  this  connection. 

RESULTS  of  experiments  CONDUCTED  IN  THE  LABORATORY 

It  was  soon  found  that  the  injury  to  plants  by  tarvia  could  be  dupli- 
cated easily  in  the  laboratory,  and  experiments  have  been  made  for  the 
purpose  of  determining  whether  or  not  what  seemed  to  be  facts  at  the 
time  of  the  accident  would  appear  imder  controlled  conditions.  For  this 
work  begonias,  Begonia  in  varieties;  ferns,  Adiantiun,  Aspidiiun  and 
Pteris;  wandering  jew,  Zebrina  pendida  Schnizl.  and  Commelina  nvdi- 
flora  Linn.;  and  geraniums.  Geranium  in  varieties,  were  used. 

In  a  comparatively  short  time  after  the  plants  were  placed  in  the  path 
of  the  fumes,  the  same  greasy  covering  of  condensed  volatile  substances 
which  collected  on  the  garden  plants  began  to  appear  over  the  plant 
surfaces.  Plants  three  to  four  feet  distant  from  the  source  of  the  fumes 
showed  an  appreciable  covering  in  about  three  hours. 

The  symptoms  of  injury  were  found  to  vary  appreciably  with  the  species. 
Leaves  of  begonias  showed  a  characteristic  sinking  of  the  upper  epidermis, 
at  first  in  small,  isolated  areas,  which  gave  a  peculiar  pocked  appear- 
ance to  the  leaves.  The  pock  marks  gradually  became  confluent,  and  the 
entire  area  lost  chlorophyll  and  turned  brown.  In  the  youngest  leaves 
the  first  symptoms  appeared  as  yellow  spots,  three  to  six  millimeters  in 
diameter,  which  when  examined,  were  foimd  in  each  case  to  be  an  injured 
area  immediately  surrounding  a  multicellular  gland.  Older  leaves  turned 
yellow  over  their  entire  surfaces  and  fell  from  the  stem. 

Ferns  treated  with  the  fumes  withered  and  dried  as  if  subjected  to 
extreme  heat.  Geraniums  showed  a  tendency  of  spotting.  In  general, 
however,  the  lower  and  older  leaves  turned  yellow,  those  of  medium  age 
turned  dark  brown  over  the  entire  surface,  while  the  youngest  and  only 
partially  unfolded  ones  showed  dark  brown  zones  on  their  margins. 

Experiments  were  performed  with  the  purpose  of  determining  whether 
or  not  the  injury  was  due  to  the  interchange  of  gases  through  the  stomata. 
Species  of  begonias  were  particularly  desirable  for  these  experiments, 
since  stomata  are  found  only  on  the  imder  surfaces  of  the  leaves.  Plants 
with  a  single  stem  bearing  about  ten  leaves  were  used.  The  stem  was 
wound  with  cotton  and  then  with  waxed  paper.  Some  leaves  were  left 
unprotected.  For  other  leaves  cork  masks  were  cut  to  fit  the  upper  and 
under  sides,  the  center  of  the  upper  mask  having  been  cut  away  until  only 
a  narrow  rim  remained.  These  masks  were  then  pinned  in  place  so  that 
the  leaves  were  entirely  protected  on  the  stomatal  surfaces,  but  exposed 

^^  McClelland,  E.  H.  Bibliography  of  smoke  and  smoke  prevention.  Mellon 
Inst.  Indus.  Research.  Bui.  2: 1-164.    1913. 


36  Phttopathologt  [Vol.  7 

on  the  upper  Rurfaces  with  the  exception  of  a  narrow  margin.  The 
plants  were  placed  so  that  the  exposed  surfaces  faced  the  fumes.  In 
all  cases  the  injury  was  as  marked  and  of  the  same  nature  as  in  the  un- 
masked leaves. 

An  experiment  was  tried  of  painting  onto  the  siirfaces  of  the  leaves  with 
a  camel's  hair  brush  the  volatile  matter  which  condensed  on  the  surface 
of  the  glass  above  the  emanating  fumes.  It  made  little  difference  whether 
it  was  applied  to  the  upper  or  lower  surface  of  the  leaf.  The  affected 
areas  showed  the  same  symptoms  as  those  treated  with  the  fumes.  The 
painted  spots  l)ecame  brown  and  finally  dried  and  dead. 

It  was  assumed  from  the  first  that  the  injury  in  the  garden  was  due  en- 
tirely to  the  effect  of  fumes  on  al>ove-ground  parts.  To  confirm  this 
assiunption,  however,  the  potii  were  either  wrapped  in  several  layers  of 
paraffined  paper,  or  coated  with  paraffin  and  their  tops  covered  with 
waxed  paper.  With  plants  thus  protected  the  results  recorded  above 
were  obtained. 

SUMMARY 

The  results  may  \yo  sunmiarized  as  follows: 

1.  The  fumes  from  the  compound  known  as  tarvia  are  highly  injurious 
to  vegetation. 

2.  liCaves  whose  surfa<*es  were  painted  with  the  oily  matter  which  col- 
lected on  a  ccH)l  gliiw  plate  over  the  emanating  fumes  showed  the  same 
symptoms  of  injury  as  did  those  treated  with  the  fumes.  This,  together 
with  other  evidenr<%  indi(*ated  that  the  injury  was  due  in  large  part  at 
IcNist  to  the  c<»nstituents  of  the  volatile  sul)stances  which  condensed  in 
the  fonn  of  an  oily  c*oating  on  the  surfaces  of  the  plants. 

3.  Plants  with  no  stomata  on  the  up|M»r  surfaces  of  their  leaves  were 
pnitected  in  resjKTt  to  all  other  surfac€»s,  and  so  placed  that  only  the 
up|M»r  leaf  surface  was  subjected  to  the  fumes.  Such  plants  showed 
injury  r»f  exactly  the  s<mie  nature  as  did  tluise  with  unprotected  stoniatal 
surface's.  This  indinited  that  the  injury  did  not  involve,  to  any  extent 
at   least,  the  piissiige  of  gases  through  stomata. 

4.  In  a  ."iufficient  numlxT  of  ex]M'rimcnts  the  soil  and  under-gnmnd 
structures  were  protected  from  the  fumes,  showing  that  the  injury*  wa.«* 
due  t«>  the  action  of  the  fumes  on  aerial  fmrts. 

').  The  injury  varied  with  the  distaixr  from  the  escaping  fumes,  the 
teiii|N*rature  of  the  melting  tar,  the  age  of  the  plant  structures,  and  the 
^|M'cies  used. 

DaKTMOCTII  (^oLLI-^iK, 

ll-Wdvwi,  N.  H. 


SOUR  ROT    OF  LEMON   IN  CALIFORNIA* 

Clayton  O.   Smith 
With  Two  Figures  in  the  Text 

The  fungus  causing  the  decay  described  in  this  paper  was  first  iso- 
lated some  years  ago  from  lemons  which  were  originally  infected  with 
the  brown  rot  fungus  Pythiacystis  ciirophthora.  Artificial  inoculations 
made  at  that  time  on  green  lemons  with  a  pure  culture  of  the  organism 
gave  negative  results,  and  no  further  attention  was  given  to  it  until  in 
1915.  The  method  of  development,  morphology  and  general  charac- 
teristics of  the  fungus,  noted  at  that  time,  were  similar  to  those  described 
in  the  present  study.  The  decay  has  been  found  in  many  of  the  lemon 
packing  houses  of  ("alifornia  and  probably  occurs  more  or  less  in  all  of 
them.  The  fungus  is  not  known  to  have  caused  serious  losses  until  the 
summer  of  1915,  when  the  unusually  large  crop  of  lemons  made  it  neces- 
sary to  hold  large  amounts  of  fruit  in  storage  for  a  longer  period  of  time 
than  is  customary,  during  which  time  considerable  loss  occurred  in  the 
packing  houses  and  in  transportation.  It  seemed  to  be  especially  in- 
fectious with  fruit  picked  in  the  spring,  being  most  commonly  reported 
in  May  fruit.  The  fungus  has  also  been  found  causing  a  rot  of  Valencia 
oranges  in  transit. 

Several  popular  terms  have  been  applied  to  this  decay  such  as  sour 
rot,  slimy  rot,  watery  rot.  These  terms  are  descriptive  of  different  stages 
of  the  decay.  The  peculiar  sour  odor  is  so  constant  a  characteristic  and 
one  so  distinct  from  those  of  other  decays  of  citrus  fruits  that  the  name 
sour  rot  is  suggested  for  this  decay. 

Sour  rot  is  a  soft  decay,  during  storage,  of  citrus  fruit,  especially  of 
lemons.  The  tissue  when  infected  quickly  softens,  but  for  some  time  may 
retain  nearly  its  normal  shape.  It,  however,  changes  to  a  straw  color*, 
later  collapses,  becoming  more  or  less  slimy  with  age,  and  at  last  is  almost 
completely  changed  into  a  watery  mass,  which  in  the  packing  house  often 
drips  down  into  the  lower  fruit  of  the  stacks.  Because  of  these  charac- 
teristics the  grading  and  sorting  of  the  fruit  is  ver>^  disagreeable.  The 
softened  areas  of  the  fruit  do  not  at  first  show  any  noticeable  aerial  my- 

*  Paper  No.  38,  Citrus  Experiment  Station,  University  of  California,  Riverside, 
Calif. 

^  Dauthenay,  Henri.     Repetoire  dc  Couleurs,  p.  31,  No.  3. 


1917]  Smith:  Sour  Rot  of  Lemon  39 

nally  described  by  Ferraris^  as  Oidium  citri-aurantn,  Saccardo  and  Sydow 
later  transferred  the  fungus  to  the^enus  Oospora.  Cultures  of  the  soiu"  rot 
fungus  were  submitted  to  Professor  David  R.  Sumstine,  Peabody  High 
School,  Pittsburgh,  Pennsylvania,  for  identification,  and  he  regards  this 
species  as  belonging  to  the  genus  Oosporoidea,'  a  group  of  fungi  that  is 
now  separated  by  some  systematists  from  Oospora  because  of  the  slight 
differentiation  between  the  mycelium  and  the  sporophores.  The  fungus 
should  now  probably  be  called  Oosporoidea  citri-aurantii  (Ferraris),  but 
for  the  present  will  be  designated  as  Oospora.  The  aerial  mycelium  of 
the  sour  rot  readily  separates  into  spores  when  moimted  in  water  for 
examination,  as  does  also  the  mycehum  growing  on  the  substratum. 
Sporophores  and  chains  of  spores  are  with  difficulty  distinguished  from 
the  myceliimi. 

Ferraris*  foimd  from  his  study  and  inoculations,  that  the  fimgus  Oospora 
cUri-aurantti  caused  an  infectious  soft  decay  of  oranges.  The  individual 
points  of  infection  increased  in  size  and  coalesced.  A  strong  odor  of 
fermented  juice  and  a  disagreeable  taste  of  the  fruit  accompanied  the 
decay.  No  aerial  mycelial  growth  was  at  first  visible,  but  under  favor- 
able conditions,  a  short  very  white,  wrinkled  myceUum  developed,  form- 
ing in  contact  with  the  substratum  a  gelatinous  layer.  The  myceUum 
has  a  constant  diameter  of  about  7  m  being  described  as  being  perfectly 
yellow  and  granular  when  growing  in  the  orange  tissue.  The  color  of 
the  mycelium  of  the  sour-rot  fungus  as  observed  under  the  microscope 
when  taken  from  artificially  inoculated  oranges,  shows  a  slightly  yellow- 
ish color  but  could  hardly  be  said  to  be  perfectly  yeUow.  The  size  of  the 
conidia  as  given  agrees  very  closely  with  that  of  the  sour-rot  fungus. 
Ferraris  recorded  the  size  of  cyUndrical  conidia  as  13.5-19  x  7-7.5  m; 
oval  conidia  9-12  x  7.5  m;  spherical  conidia  about  12  /z. 

Ferraris  refers  to  certain  other  closely  related  fungi,  causing  rots  of 
citrus  fruits.  Among  these  are  Oidium  fasciculata  Berk.,  probably  synony- 
mous with  Oospora  fasciculata  Sacc.  et  Vogl.  and  Acrosporium  fascicular 
turn  Grev.,  which  is  said  to  occur  in  decaying  citrus  fruits  in  Belgium, 
Great  Britain,  Italy  and  North  America.  This  fungus  differs  from  Oospora 
citri-auraniii  in  that  the  mycelium  is  at  first  white  but  changes  to  glaucus 
with  age.     Oidium  tigitaninum  was  described*  from  CaUfornia  as  a  pow- 

*  Ferraris,  T.  Di  un  nuovi  ifomicete  parassita  nei  frutti  di  arancio.  Malpighia 
IS:.     1900. 

*  Sumstine,  D.  R.  Studies  in  North  American  Hj'phomycetes.  The  tribe  Oospo- 
reae.    Mycol.  6 :  45-61 .     1913. 

*  Ferraris,  T.     Loc.  cit. 

•Carter,  C.  M.    A  powdery  mildew  of  Citrus.     Phytopath.  5:  193-196.     1915. 


40 


Phytopatholoqt 


[Vol.  7 


dery  mildew  of  Dancy  tangerine.     It  diffcnt  in  size,  in  shape  of  span* 
Bttd  in  other  morphological  characters  from  tho  fundus  under  oonsideration. 
Ootpara  cilri'OUTantii  is  closely  rolateil  to  Oon/jom  fcidia  morphologi- 
cally, a  fact  fully  rectqpiized  by  Ferrarip,  who  found  similarity  in  conidia 


c4 


c?'* 


.\.  It.  r.  :ii-n:il  mv.  .-Iiuni  ->l...uiiiii  chain-  -f  •, 
into  n-H-  (h:it  fill..  <■'.),  a-  !.|...r.-^  K.  .-..ni.liii.  -Ii. 
lion     F.  mI.I I'li^i  ■'lioviMK  ..11  k1..I.<iI.'v 

Ki-niiiiiiiliiiii.  li\p!i:il  l.niTn-liitin.  iitui  thr  mr 
i-iuiiii^  ;iri-  f<>titi.-<l.  Il<-  :il-^i  mi'iili<>ti'<  lli<-  i 
wliicii  tliov  i»i.  tiiUKi  site  ztl.lf  to  priMhict-.  i- 


r  in  U'hirli  ih<>  omidiii! 
niiii'^  nuiiitxT  of  (tmiilia 
i:iltv  whi'Ti  ihf  niv«*elituii 


1917]  Smith:  Sour  Rot  of  Lemon  41 

itself  breaks  up  into  spores.  Certain  differences  have,  however,  been 
found  between  these  two  fungi. 

Oospora  lactis  is  probably  a  composite  species  into  which  a  number  of 
closely  allied  fungi  have  been  placed  by  systematists.  A  culture  of  Oospora 
ladiSy  with  which  the  sour-rot  fungus  was  compared,  was  furnished  by  Mrs. 
Flora  W.  Patterson.  This  culture  was  isolated  from  oysters.  A  culture 
isolated  from  the  same  source  was  also  received  from  Dr.  Charles  Thom. 

Artificial  inoculations  w4th  Oospora  lactis  from  these  two  cultures  and  with 
the  sour-rot  fungus  on  citrus  fruits  showed  that  Oospora  citri-aurantii  ia 
pathogenic,  causing  the  fruit  to  begin  to  decay  within  a  few  days.  Oospora 
lactis  at  first  produces  some  mycelial  growth  on  the  injured  tissues,  but 
the  myceliimi  does  not  appear  to  be  able  to  attack  the  tissue  adjacent  to 
the  injury  and  no  actual  decay  takes  place.  These  experiments  were 
performed  several  diflFerent  times  in  moist  chambers  on  Eureka  lemon. 
Navel  orange  and  Dancy  tangerine.  No  infection  took  place,  although 
duplicate  experiments  on  the  same  kinds  of  fruit  with  the  sour-rot  fungus 
gave  positive  results. 

The  reaction  of  Utmus  milk  with  the  two  fungi  differs.  The  sour-rot 
organism  caused  no  change  in  the  reaction  and  probably  made  but  slight 
growth.  Oospora  lactis  showed  an  acid  reaction  and  clearing  of  mediimi 
without  separation  of  the  casein. 

The  spores  of  the  sour-rot  fungus  appear  more  regular  in  size,  and  more 
cylindrical  than  those  of  Oospora  lactis. 

Artificial  inoculations  were  made  by  puncture  with  cultures  of  Oospora 
citri-aurantii  on  the  following  citrus  fruits  in  moist  chamber:  lemons, 
oranges,  grapefruit  and  tangerine.  Positive  results  were  secured  in 
moist  chamber,  the  rot  beginning  to  show  in  forty-eight  hours.  The  ripe 
or  nearly  mature  fruit  is  more  readily  infected.  Failure  to  infect  the 
green  fruit  of  lemons  has  frequently  occurred.  Inoculations  on  the  twigs 
of  a  Eureka  lemon  gave  negative  results.  Lemons  showing  the  initial 
stages  of  the  brown-rot  fungus,  Pythiacystis  citrophthora^  were  atomized 
with  a  suspension  of  spores  of  the  sour-rot  fungus.  Infection  took  place 
quickly  in  the  brown  rot  areas  and  continued  to  increase  as  the  former 
decay  advanced.  Eventually  the  surface  of  the  lemons  was  coated  with 
the  sour-rot  fungus.  Sound  fruit  when  inoculated  with  an  atomized 
suspension  of  spores  or  when  soaked  for  twenty-four  hours  in  spore-laden 
water  were  but  rarely  infected  and  then  probably  only  in  some  superficial 
injury.  Infection  of  lemons  with  the  sour-rot  fungus  evidently  only  takes 
place  through  some  injury  or  from  contact  with  infected  fruit. 

WnimER,  California 


A  DISEASE  OF  PECAN  CATKINS 

H.     H.    H  I  G  G  I  N  8 

With  Two  FiorREs  in  the  Text 

During  the  latter  part  of  April,  1916,  the  writer's  attention  was  called 
to  an  ahnonnality  of  the  catkins  (staininate)  of  pecans,  Carya  iUinoensiSf 
on  the  ExpcTinient  Station  plats.  Some,  or  in  many  cases,  all  of  the 
flowers  of  a  (*atkin  were  slightly  distorted  and  of  a  paler  green  hue.  The 
stamens  and  inner  surfa(*e  of  the  subtending  bract  were  covered  with  a 
white  sutjstance  whi<'h  at  first  glance  gave  the  impression  of  white  fly, 
but  which  on  examination  was  found  to  l>e  the  white  spore-cluster  and  basi- 
dia  of  a  fungus  l)eIonging  to  the  genus  Microstroma.  A  little  later  when 
the  pollen  was  Iteing  she<l  the  (*ontrast  between  healthy  and  diseased  catkins 
wjis  made  mon*  ronspicuous  l>y  the  failure  of  infested  anthers  to  dehisce. 

SiH'tions  of  dise:iscMl  anthers  showed  that,  while  the  tissues  in  direct 
contact  with  the  mycelium  were  not  killed  outright,  the  pollen 
grains  were  mostly  degenerate,  empty,  and  often  collapsed  shells.  The 
my(*elium  is  entirely  intercellular,  often  fonning  thick  mats  which  wedge 
the  host  cells  a|)art  and  cause  the  slight  <listortion  of  the  diseased  parts. 
Thi>sc*  myc<*lial  nuits  i)e(*ome  especially  prominent  at  points  near  \h» 
surfac*(*  whf*n>  the  large  basal  stroma  of  the  fruit-body  is  formed  in  the 
l(M>M*  sulx'pideniuil  parench>iim.  Fn)m  this  structure  the  club-shaped 
Ixisidia  push  through  tlu*  epidermis  fonning  a  small  but  (*ompact  hymen- 
iiuii  alxive  the  siu-face  of  the  host  tissue.  The  individual  thre^ids  of  the 
inten*ellular  my(*elium  and  ak<o  of  the  stnimata  are  extremely  small  and 
diflirult  to  distinguish  as  »nv\\. 

Ai>iMirently  no  toxic  sulwtancc^  or  injurious  enz\iiies  are  secreted  by 
the  fungus,  siiu*e  the  protoplasts  and  nu<'lei  in  the  infested  tissue  retain 
nearly  normal  apjM'arance.  The  clumgi^s  in  cells  entirely  isolated  by 
the  my<*<*lial  iimts  indicate  starvation  rather  tlian  toxemia.  The  pollen 
griiiL**  pn»s4»ni  similar  evi(h»n«*es  of  starvation.  The  vacuole  gradually 
enlarges  an<l  the*  protophLxmic  layer  iM^^omes  thinner  until  it  disappears 
entirely  k'aviiig  the  niipty  |M»llen-<*<*ll  walls  which  collafMc  or  retain  their 
original  slia|M*  according  to  thrir  degree  of  maturity. 

IDKNTITY    OF   THK    PAKASITE 

Of  llu*  four  HiMM'irs  of  Mi<*n)stn)ma  mentioned  in  Saccardo's  Syllcge 
Fuf\^orum,  M,  album  (Ik^m.)  Sacc.  occurs  <»n  leaves  of  oak,  M.  CycadiM 


44  PHYTOPATHOLOaV  [VoL.  7 

Allusch.  on  leiivest  of  Cyaii  rei-olut^i,  M.  unieriainuiii  Paiiimel  &  Hiuiie  on 
U-avcB  of  CnicuM  iinierictinus,  uiiti  M.  Ju^iantiin  (B<;riii([)  Siicc.  on  k-avw* 
of  JuKliinx  uiid  Citrya.  Sinrc  M.  Juglnndin  wius  uhniitlunt  rarly  in  the 
sprinK  on  U-uvoh  of  hickories,  it  wax  iil  oix-e  siiHiK-ctod  timt  \\\c  fungiin  on 
)K.-(-an  <'atkins  was  iilc-ntirul  wit)i  tliis  sjMM'ifN.  Coinjiarulivc  nicusurt^ 
nicnis  of  llic  variiiiL"  Htructurcs  of  the  funftu;'  from  the  two  hostw  Hhowctl 
however  Monie  very  markeil  <ljfTerenc<'s.  Tin-  siMiros  from  [wean  catkins 
.-.re  eyliii.lrieal.  !>  to  M  l.y  .jji,  an.l  tlios.^  from  liirkory  leav.-s  are  oval  lo 


^  Pa 


'o9 


e  CP 


m° 


^9 


,1.  rtuiOIiK  l""Jv  -li.miiiK  l.u-i.liii.  Ml.Ti|iiM:iI:i.  :ii>rl  -|«,r.'^:  H.  fr.-^li  -|.i.r.-<;  T. 
vr».|-lil.<'  r.II.  rr.>ni  .'itilit-.l»v»'.l.l  .-iil)tir<-  ..n  n.rii  iii.'m]  -.K^af.  It.  <'.-IU  from  ..I.I 
.■»Uu,.-   ..I,   ,.,nt   iti.-:>l   i.Knr.      All    X    T::>. 

ol.]iii>i!.  l>  U>  S  l.y  i..V'  The  )ia><i<lta  iw  well  as  tlu'  Klr<>ni:ila  from  which 
thiy  arjsi'  :iri'  innili  larfcer  iiiiil  ihe  iinniNr  of  lia.-<i'lia  fmni  each  stroma 
miicli  icre.-iler  ou  ihe  |M-cari. 

<  nlliiro  i>f  Uitti  forms  were  ohiaincil  arnl  eom|)arei|  on  v:irions  media. 
'Ih.-  r.-iK.ii-^v  wen-  verv  similar  in  each  ea--e.  (In  all  nic.lia  «.  far  Irictl. 
..nh  A  >e:iM.|ik<-  growth  is  formc.l.  The  '^porc^  -well  eoi.si.lerahly  an.l 
wdIuii  a  f.'u  h.inrs  U-^in  forminK  new  cells  l.y  a  hniiiliriK  jiriKi-sN,  stnin 
fi.tnutiK  :i  Mii:<1l.  i-ircnlar  white  c.ilnnv.  Ai  tirsi  short  hvj.hal  uerm  hiln'< 
^^.■„■  |.nnul  ..<-'':.siunallv,  l.ni  ihcv  HK.n  .lis^ipixarcl,  A-.  th.'  hii.l.linK 
I.MHV^s  ...nil -  Ihc  .taiiKliter  cells  lM'.'<.me  smaller  and  ..val  or  clUjitieal 


1917]  HiGGiNs:   Disease  of  Pecan  Catkins  45 

to  globose.  The  fungus  is  not  long-lived  in  cultures,  requiring  frequent 
changes  to  new  media. 

Early  in  May  direct  and  cross  inoculations  were  tried  with  fresh  spores 
from  each  host,  but  they  all  resulted  in  failure. 

Diligent  search,  for  diseased  catkins  was  made  over  several  hickory 
trees  the  leaves  of  which  were  infested  with  Microstroma  but  none  were 
found.  Neither  was  any  disease  found  on  the  leaves  of  pecan  trees, 
although  in  some  instances  they  were  almost  in  contact  with  diseased 
hickory  leaves. 

Notwithstanding  the  apparent  difference  in  tissues  attacked,  in  size 
of  spores,  basidia  and  so  forth,  it  still  seems  doubtful  that  the  pecan  fungus 
should  be  given  specific  rank.  The  more  robust  habit  on  the  catkins 
may  be  due  to  the  more  abxmdant  supply  of  food.  Therefore  for  the 
present,  it  seems  best  to  consider  the  fimgus  on  pecan  catkins  as  merely 
a  robust  variety  of  Microstroma  Juglandis  (Bereng.)  Sacc.  and  to  present 
the  following  diagnosis: 

Microstroma  Juglandis  (Bereng.)  Sacc.  var.  robustum  n.  var. 

Host  tissue  pale,  often  slightly  distorted;  myceliimi  intercellular,  form- 
ing more  or  less  dense  mats  between  the  host  cells;  fruiting  stromata  oval 
to  short  conical,  60  to  100  by  55  to  150/*,  compost  of  very  slender  inter- 
woven threads;  basidia  club  shaped,  13  to  30  by  5/*,  bearing  apically  6 
to  8  spores  on  short  sterigmata;  spores  hyaline,  one-celled,  cylindrical, 
rod-shaped,  9  to  14  by  3  to  5/*. 

Hab.     On  stamens  and  staminate  bracts  of  Carya  iUinoensis. 

Microstroma  Juglandis  (Bereng.)  Sacc.  var.  robustum  n.  var. 

Stromaiibv^  frudificantibus  subepidermids,  ovatis  vel  brevo-conids,  60  to 
100  by  55  to  85 n;  basidiis  caespitosis,  davatis,  13  to  30  by  5^.,  seanf.  odoporis; 
sporidiis  hyalinis,  cylindricis,  9  to  14  by  3  to  5ti. 

economic  importance  op  the  disease 

Since  pollen  is  always  produced  in  super-abundance  by  pecan  trees 
the  loss  of  a  comparatively  large  amoimt  is  of  Uttle  importance.  Since 
however,  on  some  trees  fully  one-third  of  the  pollen  was  destroyed  one 
can  readily  see  how  the  disease  may  become  serious  in  the  near  future. 
At  present  so  Uttle  is  known  as  to  the  life  history  of  species  of  Microstroma 
that  any  suggestion  as  to  control  measures  is  almost  valueless. 

Observations  in  the  Station  orchard  during  the  past  spring  indicated 
that  few  or  no  commercial  varieties  are  entirely  immune;  but  the  attack 
was  much  more  severe  on  some  varieties  than  on  others.  Similar  observa- 
tions were  also  made  in  orchards  around  Albany,  Georgia. 

Geoboia  Agricultural  Experiment  Station 
Experiment,  Georgia 


SOME  NEW  OR  LITTLE  KNOWN  HOSTS  FOR  WOOD- 

DESTROYING  FUNGI 

Akthuk  S.  Rhoadb 

Despite  the  great  extent  to  which  wood-destroying  fungi  have  beeo 
collected,  but  comparatively  little  attention  has  been  paid  to  the  host 
species  on  which  they  occur.  One  frequently  finds  in  herbaria  good 
collections  the  practical  value  of  which  is  greatly  reduced  by  being  de- 
ficient in  this  respect.  Within  the  last  few  years,  however,  increasing 
attention  is  being  paid  to  the  host  species  with  the  result  that  many 
new  hosts  have  been  established  and  many  fungi  which  formerly  were 
thought  to  be  confined  entirely  to  the  wood  of  deciduous  or  coniferous 
trees  are  now  kno^-n  to  occur  on  both. 

In  his  ovn\  collecting  work  the  writer  always  has  been  particularly 
interested  in  the  hosts  for  wood-destroying  fungi  and  frequently  collects 
for  host  species  alone.  In  looking  over  his  lists  recently  a  few  species 
were  noted,  some  of  which  apparently  never  have  been  reported.  All 
but  two  of  the  collections  cited  here  have  been  made  by  the  writer  him* 
self  or  in  conjunction  with  others,  cither  in  the  states  of  Pennsylvania  or 
New  York.  The  following  host  species  for  wood-destroying  fungi  are 
believed  to  be  new  or  at  least  little  known. 

Coriolus  versicolor^ 

On  dead  trees,  fallen  trunks,  and  Atumpd  of  Tsuga  canadensis*  (Pa.  and  N.  Y.). 
On  rustic  fence  rails  of  Juniperus  vtrginiana  (Pa.). 

On  fallen  trunks  and  stump  of  Abies  baUamea  (N.  Y.).  This  species  was  noted 
as  a  host  by  Dr.  L.  H.  Pennington  on  two  occasions  in  the  .\dirondack  region. 

Coriolus  nigromarginatus 
On  a  dpa<l  trunk  of  Tsuga  canadensis  aMsocJAtcd  with  Coriolus  abietinus  (N.  Y.). 

Coriolus  prolificans 

On  d(*ad  trunks  of  Tmuja  canadensis  (Pa.  and  N.  Y.).  Numerous  sporophores 
occaAiorially  are  found  either  pure  or  asfl4N*iBttHl  with  (\yriolus  aitietinus.     It  pro- 


*  The  nomenclature  for  fungi  used  in  this  paper  is  that  of  William  A.  Murrill. 
((Agaricales)  Polyiwraccae  (pars).  North  Am.  Fl.  9:  1-7*2.  1907;  (.\garicales) 
Polyporareae  ironcl).     North  Am.  Kl.  9:  73-131.     IIKW.I 

*  The  nom«*nrlaturc  for  tr(»<*s  \\mh\  in  this  paper  xn  that  of  George  B.  Sudworth. 
(Check  lint  of  \\u*  forest  trees*  of  the  Tnitwl  States,  their  names  and  ranges.  U.  8. 
Dept.  Agr  ,  Div.  Forentry  Hul    17:  144  p.  IHIW.) 


1917]  Rhoads:   Hosts  for  Fungi  47 

duces  a  sap-rot  in  hemlock  that  is  indistinguishable,  macroscopically  at  least,  from 
that  caused  by  Cabietinus, 

CorioleUus  sepium 

On  rustic  fence  rails  of  JuniperiLS  virginiana  (Pa.). 
On  stump  of  Tsuga  canadensis  (N.  Y.). 

Tyromyces  comus 
On  rustic  fence  rails  of  Junxperus  virginiana  (Pa.). 

Bjerkandera  adiista 

On  rustic  fence  rails  of  Juniperus  virginiana  (Pa.). 
On  stump  of  Thuja  occidenialis  (Pa.) . 

Porodisculxis  pendiUis 

On  branches  of  fallen  trunks  of  Juglans  cinerea  (N.  Y.).  This  fungus  usually  is 
collected  on  wood  of  Caatanea  dentata  but  occurs  commonly  about  Syracuse  on  butter- 
nut wood. 

PolyporiLS  Polypcrus 
On  slash  of  Tsuga  canadensis  (Pa.). 

Pycnaporus  cinnabarinus 

On  a  fallen  sapling  of  Tsitga  canadensis  (Pa.). 
On  log  of  Picea  rubens  in  corduroy  road  (N.  Y.). 

Hapalopilus  gihrus 
On  a  dead  sapling  of  Tsuga  canadensis  (Pa.). 

Ischnoderma  fvliginosum 
On  dead  trunk  of  Pinits  strobus  associated  with  Coriolus  abietinus  (N.  Y.). 

Elfvingia  megaloma 

On  dead  trees,  fallen  trunks,  and  stumps  of  Tsuga  canadensis  (Pa.  and  N.  Y.). 
On  stump  of  Abies  balsamea  (N.  Y.). 

Ganoderma  Tsugce 

On  or  in  close  contact  with  stump  of  Pinus  rigida  (Pa.). 

On  stump  of  Picea  excelsa  (Pa.)- 

On  a  much  decayed  stub  of  Betula  liUea  (N.  Y.).  A  fine  large  specimen  was  col- 
lected on  the  latter  host  at  Cranberry  Lake,  New  York,  and  was  fully  as  typical  as 
those  frequently  found  on  hemlock  trunks  in  that  region. 

GkeophyUum  trabeum 
On  rustic  fence  rails  of  Juniperus  virginiana  (Pa.). 


48  Phttopatholoqt  [Vol.  7 

GhBophyUum  hirsutum 

On  A  soft  maple  log  in  a  wharf  at  Oneida  Lake,  New  York.  Occasional  aporo- 
pborea  were  anoetated  with  its  near  relative,  Gloeophyllum  trabeum.  Tlie  wood 
was  either  that  of  Acer  $aecharinMm  or  Acer  rttbrum^  but  judging  from  the  dominance 
of  the  silver  maple  in  the  lowlands  of  this  region,  it  probably  was  the  former  species. 

On  stump  and  adjacent  log  of  PrunuM  avium  (Pa.)*  Near  State  College,  Pa., 
•porophores  were  found  at  various  times  associated  with  Gloeophyllum  irabtMm  on 
a  stump  and  nearby  log  from  the  same  tree. 

On  fallen  trunk  of  Betula  luUa  (N.  Y.).  A  collection  of  this  plant  was  found  in 
the  herbarium  of  the  New  York  State  College  of  Forestry  and,  although  no  host 
was  recorded,  a  few  s|>prophoree  had  ample  bark  attached  to  them  to  be  positively 
certain  that  they  grow  on  yellow  birch. 

GkBoporua  e(mchoides 

On  an  old  sporophore  of  InonoluM  dryophilue  (Pa.).  In  making  a  collection  of 
the  former  plant  from  a  black  oak  log  an  old  sporophore  of  Inonoiui  dryopkUuB  waa 
found  on  the  log  that  also  was  well  covered  with  sporophores  of  OUdoporuM  coneAoidss 
and  seemed  to  be  as  good  a  host  for  this  plant  as  the  wood  of  the  log. 

The  New  York  State  College  op  Forestry 
At  Syracuse  University 
Syracuse,  New  York 


NOTES  ON  CRONARTIUM  COMPTONLE  III 

Perlet  Spauldinq 

In  1908  the  writer  collected  a  specimen  of  Cronartium  CamptonuB 
Arthur  on  a  young  tree  of  Pinus  rigida  at  Burlington,  Vermont.  Since 
that  time  all  available  information  concerning  this  fungus  has  been  ao- 
ctunulated,  and  all  the  experimental  work  possible  has  been  done.  Three 
brief  papers^  have  been  published  giving  some  of  the  more  important 
facts  which  have  been  learned.  It  is  proposed  in  the  present  paper  to 
state  very  briefly  some  results  secured  in  more  recent  investigations. 

The  pine  hosts  of  Cronartium  Comptanias,  which  have  been  previously 
reported  by  various  writers,  are  Pinus  rigida  Mill.,  P.  sylvestria  L.,  P. 
maritima  R.  Br.,  P.  austriaca  Hoess.,  P.  divaricata  Ait.,  P.  echinata  Mill., 
P.  montana  Du  Roi,  P.  ponderosa  Laws.,  P.  contorta  Loud.,  P.  virginiana 
Mill.,  and  P.  tceda  L.  In  the  years  1915  and  1916  Cronartium  Comp^ 
tonicB  has  been  received  by  the  writer  from  various  locaUties  on  the  follow- 
ing new  pine  hosts:  Pinus  densiflora  Sieb.  &  Zucc.  (one  locality),  P. 
jeffreyi  Oreg.  Comm.  (two  localities),  P.  larido  Poir.  (one  locahty),  P. 
mugho  Poir.  (three  localities)  and  P.  resinosa  Alton  (one  locaUty;  three 
other  localities  are  known  but  no  specimens  could  be  secured). 

Successful  inoculations  have  been  made  by  the  writer  and  his  colleagues 
named  below,  for  the  first  time,  so  far  as  can  be  determined  from  pub- 
lished statements,  from  several  pines  to  the  alternate  hosts.  Uredinia 
were  produced  on  plants  of  Comptonia  asplenifolia  L.  with  aeciospores 
from  Pinus  tceda  (one  test  made),  P.  austriaca  (2  tests),  P.  rigida  (4  tests) 
P.  mugho  (3  tests),  P.  resinosa  (1  test),  P.  jeffreyi  (1  test),  P.  larido  (1 
test).  Uredinia  on  Comptonia  were  successfully  used  to  produce  uredinia 
on  Comptonia  and  Myrica  gale,  Uredinia  from  Myrica  gale  produced 
uredinia  on  Comptonia.  These  are  the  first  successful  inoculations  with 
uredinospores  to  be  reported.  In  the  winter  of  1914-15  a  special  effort 
was  made  to  seciu'e  Uving  plants  of  all  the  species  of  Myrica  growing  in 
this  coimtry.  A  stock  of  the  following  species  was  obtained  largely 
through  the  efforts  of  G.  G.  Hedgcock  and  E.  P.  Meinecke:  Myrica 
gale  L.,  M.  califomica  Cham.,  M,  cerifera  L.,  M.  carolinensis  Mill.,  M. 

'Spaulding,  Perley.  Notes  on  Cronartium  Comptonise.  Phy topath.  8 :  62.  F.   1913. 

.    Notes  on  Cronartium  Comptonise  II.    Phy  topath.  8:  306-310.  D.    1913. 

.    Notes  on  Cronartium  Comptonise  and  C.  ribicola.    Phy  topath.  4:  409.  D. 

1914. 


50  Phytopathology  (Vol.  7 

inodora  Bartr.,  M.  pumila  Michx.,  as  well  as  CompUmia  asplenifolia. 
Mr.  G.  F.  Gravatt  and  Dr.  G.  R.  Lyman  in  1915  made  inoculations  under 
the  writer's  direction.  Five  different  series  of  inoculations,  with  aecio- 
spores  from  as  many  different  species  of  pine,  were  made.  Theresulta 
were  as  follows: 

3  plants — CompUmia  asplenifdia — uredinia  produced  on  all. 
7  plants — Mj/rica  gale — ^uredinia  produced  on  all. 

9  plants — Myrica  caroHnerms — no  infection. 

4  plants — Myrica  califamica — no  infection. 

5  plants — Myrica  inodora — no  infection. 

3  plants — Myrica  pumila — no  infection. 

4  plants — Myrica  cerifera — no  infection. 

A  single  plant  of  3/.  carolinensis  was  inoculated  repeatedly  in  1916  by 
the  writer  without  visible  results  other  than  yellow  spots  on  the  leaves, 
which  are  thought  to  be  due  to  some  other  cause.  Nimierous  successful 
inoculations  have  l)een  made  on  CompUmia  asplenifoUa:  i.e.,  a  total  of  two 
in  1912,  eleven  in  1913,  two  in  1914,  nine  in  1915,  and  fourteen  in  1916. 
A  lesser  numljer  has  been  made  on  Myrica  gafe,  which  gives  much  less 
striking  results.  The  total  number  of  such  successful  inoculations  on 
Myrica  gale  is:  seven  in  1915  and  four  in  1916. 

In  1912  the  writer  l)egan  a  series  of  annual  observations  in  an  area  of 
several  acres  near  I^kc  George,  New  York,  quite  thickly  covered  with 
natural  reprcKluction  of  Pinus  rigida,  in  which  Cronariium  CompUmia 
occurs  as  a  native  parasite.  The  size  of  the  trees  within  the  area  ranges 
from  twenty  feet  in  height  downward.  Ver>'  few  are  as  small  as  two  feet 
in  height  and  there  seem  to  l)e  no  ver\'  young  see<llings  now  appearing. 
Comptonia  ojsplenifolia  gro^-s  naturally  throughout  the  area  so  that  condi- 
tions are  excellent  for  the  spread  and  development  of  the  disease.  These 
observations  have  continue<l  until  the  present  time,  thus  covering  a  period 
of  five  years.  An  effort  has  been  made  to  keep  numl)ered  labels  on  all  of 
the  (iis(»jised  trees,  hut  with  indifferent  success  Ix^cause  of  curiosity  or 
mischief  in  people  who  luippened  to  see  them.  Several  significant  facts 
liave  l)een  learned  howevcT.  On  pines  Cronartium  CompUtnict  fruits  for 
a  iK»ri(Ml  of  seven  or  eight  w<M»k.**,  the  time  of  maximimi  fruiting  being 
alMMit  Jiine  first  <'on8iderably  earlier  than  the  Tiriter  at  first  supposed. 
The  numlK»r  of  diseasc^d  trcH»s  killed  annually  by  the  fungus  has  been  sur- 
prisingly unifonn,  mnging  from  eight  to  eleven.  In  1916  the  obecrva- 
tion.H  were  made  earlier  than  iLsual  and  a  greater  total  niunber  of  diseased 
inN-s  were  unexi>e<'t<»<||y  found.  There  is  evidence  that  a  small  munber 
of  tr(H»s  are  annually  infeeted  for  the  first  time  and  it  is  hoped  to  learn 
this  numtxT  in  the  future.     It  is  well  establi.Hhed  tliat  a  tree  which  once 


1917]  Spaulding:  Cronabtium  Comptoniae  51 

bears  fruit  of  the  fungus  almost  always  bears  an  annual  crop  of  such  fruits 
until  the  tree  dies.    In  some  cases  a  dying  tree  fails  to  produce  them, 
but  on  the  other  hand,  recently  killed  trees  are  often  found  with  aecia 
on  them.    While  the  annual  loss  is  not  great,  it  is  a  serious  loss  when 
continued  indefinitely.    Moreover  we  have  excellent  reasons  for  believing 
that  Pinvs  rigida,  to  which  the  preceding  statements  apply,  is  much  less 
susceptible  to  the  disease  than  are  P.^onderosa  and  P.  cantarta.    The  loss 
in  some  instances,  with  the  latter  two  species,  has  been  total.' 
Ofpicb  op  Investigations  in  Forest  Pathology 
Bureau  op  Plant  Industry 
Washington,  D.  C. 

'Kauffman,  C.  H.  and  Mains,  E.  B.    An  epidemic  of  Cronartium  Comptonis  at 
the  Roscommon  state  nurseries.    Mich.  Acad.  Sci.,  Ann.  Rept.  17:  188-189.    1915 


FURTHER  NOTE  ON  A  PARASITIC  SACCHAROMYCETE 

OF  THE  TOMATO 

Albert  Schneider 

Since  the  appearance  of  the  recent  article  on  a  parasitic  Saccharomyoete 
of  tomato^  it  has  been  determined  that  the  fungus  described  unquestion- 
ably belongs  to  the  genus  Nematospora  of  Peglion.'  In  its  morpho- 
logical characteristics  it  is  closely  similar  to  Nematospora  Coryli  PegL, 
which  attacks  the  fruit  of  the  hazel  bush  (Carylus  aveUana).  Peglion, 
however,  makes  no  reference  to  the  gametic  origin  of  the  ascus  nor  does 
he  note  the  two  cells  of  the  ascospore.  He  also  fails  to  recognise  the 
arthroHpores  and  includes  them  imder  ''Anomale  vegetative  Formen." 
These  and  other  morphological  as  well  as  biological  differences  make  it 
clear  that  the  Xematospora  Coryli  of  Peglion  and  the  fungus  under  con- 
sideration are  two  distinct  species.  Both  are  true  parasites  and  appear 
to  occiu-  in  wanner  countries  (southern  Italy,  southern  California  and 
Cuba)  and  perhaps  also  in  semitropical  and  tropical  countries. 

The  Nematospora  of  the  tomato  (Lycopersicum  esculentum)  is  appar- 
ently a  new  species  and  the  following  name  is  therefore  proposed: 

Nematospora  Lycopersid  n.  sp. 

Asci  of  gametic  origin  soon  becoming  free  from  associated  cells,  cylin- 
drical with  rounded  ends,  60  to  70m  in  length;  ascospores  in  two  groups 
of  four  spores  each,  two-celled,  slender,  with  pointed  ends,  slightly  ridged 
at  transverse  septum,  50  by  4.5^;  ascospores  liberated  by  dissolution  of 
ascus  wall  and  held  together  somewhat  in  groups  of  4  by  motionless  fla- 
gellae;  flagellae  50  to  lOO/i  in  length;  arthrospores,  of  non-gametic  origin, 
spherical  to  ampulliform,  25m  in  diameter.  Two  other  cell  forms  also 
found:  (1)  much  elongated,  filamentous  cells;  (2)  elliptical  and  ovoid  cells, 
gametic  in  function,  new  celU  forme<l  in  bipolar  direction  by  apical  bud- 
ding and  also  by  apico-lateral  budding  at  cell  unions.  The  elliptical  and 
ovoid  cells  alone  are  gametic  in  function. 

Habitat.  Parasitic  on  nearly  ripe  and  ripe  fruit  of  Lycopersicum  es* 
culenium,  southern  California,  Cul>a  and  Mexico. 

'Srhnridcr.  Alljert.  A  paranitic  Saccharomycetc  of  the  tomato.  Phytopatholofj 
4:  395-399.     1910. 

•IVglion,  Viiiorio.  ToJior  dir  Ncmatoapora  Coryli  Pegl.  Ccntralbl.  f.  Bakt. 
Abt.  2,  8:  754-761.     1901. 


1917]        Schneider:  Parasitic  SAccHAROBiTCETE  of  Tomato  53 

Nematospora  Lycopersid  sp.  nov. 

Ascis  cylindratis,  terminate  orbiculato;  60-70/i  in  longitudine;  sporidiis 
8;  dispositis  struibus  duo,  sporidiis  4.  Ascus  mox  ex  cellis  prehensis  li- 
beratus  est.  Tnnicae  asconun  in  maturitate  solventur  et  sporidiis  liber- 
antur.    Plurimi  asci  origine  gametata  sunt. 

Sporis  ascpnim  bi-cellulatis  tenuibns,  fusiformibus,  flagello  uno.  Spo- 
ridiis 50  X  4.5m,  flagello  50-100m. 

Arthrosporis  non-gametatis,  plerumque  sphaeroidis,  25/i. 

Cellulis  vegetativiSy  eUipticis,  ovatis  ad  filaris  nonramosis,  multipli- 
cantibus  gemmatando  apiculo-laterali  apicnlatoque.  Cellulis  ellipticis  et 
ovatis  solis  sunt  gametatis. 

Hab.    In  fructo  Lycopersici  esculenti,  terris  calidis  et  tropieis. 

Acknowledgments  are  hereby  made  to  Dr.  Roland  Thaxter  and  Prof.  H. 
W.  Anderson  for  calling  the  writer's  attention  to  the  Nematospora  of 
Peglion. 

Uni\ersity  op  California 
College  of  PnARBiACY 
San  Francisco,  Calif. 


PHYTOPATHOLOGICAL  NOTES 

Albany  conference  on  white  pine  blister  rust.  A  joint  meeting  of  the 
North  American  Committee  for  the  Control  of  the  Pine  Blister  Rust  and 
the  cooperators  of  the  United  States  Department  of  Agriculture  was  held 
at  Albany,  New  York,  November  20  and  21.  The  meeting  was  attended 
by  a  representative  body  of  men  from  the  states  of  New  Hampshire, 
Vermont,  Massachusetts,  Rhode  Island,  Connecticut,  New  York,  New 
Jersey,  Pennsylvania,  Virginia,  Indiana,  Wisconsin  and  Minnesota,  and 
from  the  Dominion  of  Canada  and  the  United  States  Department  of 
Agriculture.  The  state  foresters,  pathologists,  and  nursery  inspectors  most 
intereste<l  in  the  fight  for  the  control  of  the  disease  were  present. 

A  brief  re|x>rt  from  each  state  and  from  Canada  gave  the  latest  news 
concerning  disea^  survey  and  eradication  work.  The  reports  show  the 
general  epiphytotic  of  the  blister  rust  in  New  England  and  eadt  of  the 
Hudson  River,  with  comparatively  few  centers  of  infection  in  New  York, 
Pennsylvania  and  New  Jersey,  one  infection  center  in  Ohio,  two  in  Wis- 
consin, and  four  in  Minne«K>ta.  A  hasty  survey  made  of  the  western 
half  of  the  count r>'  faile<l  to  show  any  blister  rust  of  white  pine  present. 

It  developed  tliat  the  matter  of  control  of  the  blister  rust  in  the  New 
England  states  resolved  itself  into  the  practicabilit>'  of  the  eradication 
of  currant  and  gooseberry'  bushes  on  a  large  scale.  The  control  of  the 
blister  rust  in  the  I^ke  States  was  shown  to  be  on  a  somewhat  different 
basis,  for  in  that  region  the  spots  of  infection  known  are  very  few.  Here 
the  total  eradi(*ation  of  all  white  pines  and  Ril)e8  near  the  infection  cen- 
ter is  l>eing  carried  out. 

The  Conmiittee  passe<l  resolutions  favoring  adequate  legislation  which 
would  |)ennit  states  to  carr>'  out  the  eradication  or  control  work  neces- 
sary', following  largely  the  Sanders  model  horticultural  inspection  bill. 
They  also  favored  ad«|uate  appropriiitions  by  the  states  to  carry  on 
eradication  work  and  by  the  Fcnleral  (Sovernment  to  carry  on  the  sur- 
vey an<l  ex|KTimental  work.  The  Committee  favored  a  Federal  quaran- 
tine prohibiting  shipment  of  five-needled  pines  and  all  species  of  Ribes 
from  the  eastern  half  of  the  countrj'  to  any  part  of  the  country  west  of 
Minm^sota,  Iowa.  Muwouri.  Arkansas  and  Ix)uiBiana.  A  state  qxiar- 
antine  was  also  reconanended  pn>hibiting  shipment  of  five-needled  pines 
and  RilK»s  from  inf(»<'ted  stat<»s  to  others  not  infected. 

A  national  law  was  urfccnl  prohibiting  the  importation  of  all  plants 


1917]  Fhttopatholoqical  Notes  55 

from  any  other  continent  into  the  United  States  except  through  the 
United  States  Department  of  Agriculture  solely  for  scientific  and  experi- 
mental purposes. 

Rot  G,  Pierce 

Corn  disease  caused  by  PkyUachora  graminis.  During  the  euminer  of 
1915,  an  apparently  undescribed  disease  of  corn  was  observed  by  F.  L. 
Stevens  in  Porto  Rico,  Leaves  were  collected  from  the  diseased  fields 
in  numerous  localities  in  Porto  Rico,  and  a  study  of  the  disease  based 
entirely  on  this  herbarium  material  has  been  made  at  the  University  of 
Illinois. 


Fig.  1.    Pbtllacrora  graiunis  on  Corn 
PortioD  of  a  leaf  shows  strcmata  on  upper  and  lower  surfaces 

The  disease  manifests  itself  as  well-defined,  aubcarbonaceous  spots, 
either  dmall  and  numerous  or  comparatively  large  and  sparaely  distributed, 
and  in  either  cade  surrounded  by  a  narrow,  yellowish-brown  halo.  The 
infection  is  local,  confined  to  the  leaf  and  the  leaf  sheaths,  and  is  visible 
on  both  upper  and  lower  surfaces. 

The  spots  are  due  to  the  formation  of  stromata  in  the  infected  tissue. 
Embedded  in  the  stromata  are  perithecia  consisting  of  depressed  cavities 
surrounded  by  walls  made  up  of  dark-brown  mycehum  and  bearing  at 
the  top  a  comparatively  small  ostiole. 

The  mycehum  in  newly  invaded  tissue  is  slender  and  hyaline.  It 
later  becomes  dark  brown,  filling  the  leaf  tissue  of  the  infected  area  with 
a  network  of  hyphae. 


66  Phytopathology  [Vol.  7 

The  asci  are  numerous.  They  are  cylindrical  and  in  each  sBcua  are 
produced  eight  unicellular,  hyaliqe,  thin-walled  spores. 

The  fungus  causing  the  disease  has  been  identified  as  PhyUaehara 
graminus, 

A  report  including  a  detailed  description  of  the  disease  and  fungus, 
together  with  notes  concerning  the  generic  and  specific  relationship,  will 
be  read  before  the  Illinois  Academy  of  Science  at  its  next  meeting. 

Nora  E.  Dalbey 

Tylenchus  triiici  on  wheal.  In  August,  1915,  specimens  of  diseased 
wheat  plants,  which  had  just  been  received  from  Dr.  J.  H.  Reisner,  of 
the  University  of  Nanking,  Nanking,  China,  were  kindly  turned  over 
to  the  \vTiter  by  Dr.  H.  B.  Himiphrey,  of  the  OflSce  of  Cereal  Investigations, 
Bureau  of  Plant  Industry.  In  transmitting  this  material  by  letter  Dr. 
Rei^ner  said,  *'Tlie  disease  has  become  more  widespread  every  year  for 
the  last  three  or  four  years  and  is  causing  great  money  losses." 

A  microscopic  examination  of  the  wheat  heads  showed  that  practi- 
cally all  of  their  glumes  contained,  in  place  of  normal  kernels,  dark  galls 
filled  with  an  almost  innimierable  number  of  motionless  but  living  larvae 
of  the  nematode,  Tylenchus  triiici  Bauer,  which  has  been  known  as  a  serious 
pest  in  Kurope  since  1745.  The  parasite  has  been  found  in  Sweden, 
Holland,  (lemiany,  Austria-Hungary,  Switzerland,  Italy,  England,  and 
Australia,  but  so  far  as  known  has  never  been  reported  from  China  before. 
Johnson*  recorded  in  1909  the  occurrence  of  what  undoubtedly  is  the 
same  species  on  wheat  from  a  few  widely  separated  sections  in  the  United 
States,  but  as  no  reports  of  its  appearance  l>efore  or  since  that  date  have 
iK'on  found,  it  is  quite  unlikely  that  the  eelworm  has  become  well  estab- 
HsImmI  in  the  wheat  areas  of  this  country.  Whether  the  closely  related 
siH»ci(»s  of  Tylenchus  found  by  Bessey*,  the  writer,  and  others  on  several 
difTcrent  grasses  in  various  parts  of  the  United  States  is  identical  with  the 
fonn  on  wheat  has  not  been  determined.  Some  European  investigators, 
however,  regard  Tylenchus  triiici  as  a  highly  specialized  parasite  of  the 
wheat. 

The  infected  heads  of  wheat  are  usually  shorter  and  thicker  than  nor- 
mal heads  and  contain  glumes  which  spread  out  almost  at  right  angles 
to  the  fruit  stem.  In  place  of  normal  seed,  dark,  hard  galls,  incapable 
of  g(*rmination  ami  full  of  lar\'ae,  are  to  \ie  found.  Because  of  these 
effects  on  the  host  the  disease  has  merited  such  descriptive  names  as  ear- 
coc'kles,  purples,  false  ergot,  etc. 

*  Johnwm.  VAw,  C     NuU'S  on  a  nomatodo  in  wheat.    Science  n.  a.  SO:  576.     1900. 

*  B^aaey,  Krneat  A.    A  m*matodc*  diaeaap  of  graasea.    Science  n.  a.  21 :  391.     1006« 


1917]  Phytopathological  Notes  57 

Active  larvae  enter  the  young,  tender  tissues  of  the  wheat  flower, 
extract  -food  therefrom,  tnature,  and  lay  eggs,  which  in  tiun  give  rise  to 
another  generation  of  larvae.  After  reaching  a  certain  stage  of  develop- 
ment some  of  the  subsequent  generations  of  larvae  become  coiled  and 
dried  out  in  the  matured  seed  coats  of  the  host  and  are  capable  of  re- 
maining in  this  inactive  condition  for  long  periods.  Under  favorable 
conditions  of  moisture  and  temperature  the  eelworms  may  escape  from 
the  seed,  attack  the  leaf  and  stem  parts  of  wheat  seedlings,  causing  them 
to  become  wrinkled,  distorted,  or  swollen,  and  finally  enter  the  embryonic 
seeds. 

It  has  seemed  desirable  to  bring  the  above  data  to  general  attention, 
in  the  hope  that  active  measures  will  be  taken  both  to  prevent  the  in- 
troduction of  this  parasite  along  with  wheat  importations  from  infected 
coimtries  and  to  stamp  out  the  pest  wherever  it  is  foimd  in  this  coimtry. 

L.  P.  Byars 

The  Botanical  Society  of  Washington.  The  following  officers  have  been 
elected  for  the  ensuing  year: 

President,  Mr.  T.  H.  Kearney;  Vice-President,  Mr.  Edgar  L.  Brown; 
Recording  Secretary,  Mr.  Charles  E.  Chambliss;  Corresponding  Secre- 
tary, Dr.  H.  L.  Shantz;  Treasurer,  Mr.  F.  D.  Farrell. 

Mr.  A.  S.  Hitchcock  was  nominated  by  the  Society  for  the  position 
of  Vice-President  of  the  Washington  Academy  of  Sciences. 

Personals.  Mr.  Chas.  S.  Reddy,  of  the  University  of  Wisconsin,  has 
been  appointed  as  assistant  plant  pathologist,  and  Mr.  A.  M.  Christen- 
sen,  of  the  North  Dakota  Experiment  Station,  as  an  agent,  in  Cereal 
Disease  Investigations,  Bureau  of  Plant  Industry,  with  headquarters 
at  Fargo,  North  Dakota,  where  they  are  engaged  in  the  investigation 
of  cereal  diseases  in  cooperation  with  the  North  Dakota  Station. 

Mr.  F.  A.  McLaughlin,  instructor  in  botany  at  the  Massachusetts 
Agricultural  College,  has  been  granted  a  year's  leave  of  absence  for  grad- 
uate study  at  the  University  of  Chicago. 

Mr.  W.  L.  Doran,  for  the  last  two  years  graduate  assistant  in  botany 
at  the  Massachusetts  Agricultural  College,  has  been  appointed  instructor 
in  botany  and  assistant  botanist  at  the  New  Hampshire  Agricultural 
College  and  Experiment  Station. 


ABSTRACTS  OF  PAPERS  PRESENTED  AT  THE  EIGHTH  AN- 
NUAL MEETING  OF  THE  AMERICAN  PHYTOPATHOLOGICAL 
SOCIETY,  NEW  YORK  CITY,  DECEMBER  26^,  1916 

Evidence  oj  the  over  wintering  of  Cronartium  ribicola.     Perlet  SpaulDING 

Numcrouii  inHtances  have  been  noted  whore  largo  lots  of  black  currants  were  very 
heavily  infected  with  Cronartium  ribicola  one  summer  and  not  the  next.  In  the 
Geneva  New  York  case  the  disease  was  present  upon  pines  and  these  in  the  writer's 
opinion  started  the  disease  each  spring.  Cooperative  experiments  with  Stewart, 
in  which  500  heavily  infected  black  currants  were  used,  resulted  in  no  disease. 
Furthermore,  the  writer  has  had  during  the  past  sev(*n  years  in  the  greenhouses  at 
Washington,  hundreds  of  KilK»s  plants  of  more  than  thirty  species,  which  have  l>een 
UM>d  in  inoculation  ox|>orimonts.  In  no  case  has  the  disease  ever  appeared  upon 
thest*  the  next  w^ason  until  artificial  inoculations  had  l>oon  made.  Uniform  success 
has  l)e<*n  obtained  |]i*rs<>n»lly  in  locating  the  diseased  pines  from  the  areas  occupied 
by  the  first  gi'noration  of  un'doKporoM  in  the  field.  Field  observations  seem  to  indi- 
cate that  the  dis(*am*  has  lieen  shipfied  into  now  localities  on  infected  Ril)es.  In- 
fections of  petioles  are  not  as  rare  as  at  first  supposed.  No  evidence  of  bud  infection 
by  way  of  the  petiole  has  yet  Ix^en  s<*cured.  Direct  examination  of  buds  on  infected 
plants  has  also  failod  to  show  the  presence  of  the  disease. 

The  control  of  white  piri£  hlinter  rwtt  in  small  areas.     W.  H.  Ra.vkin 

The  control  of  white  pine  blister  rust  has  l>een  att4>mpted  in  eighty-five  forest 
plant ingH  mad<»  with  imported  stock  in  New  York  State.  Diseased  or  suspicious 
trees  and  all  currants  and  gooseberries  within  five  hundred  feet  of  the  plantings 
were  n^nowd.  Thirty-six  plantings  ha\'e  shown  diseased  trees  since  1909;  twenty 
since  HUl;  sewnti^en  sinci*  1912;  fifteen  since  1913;  nine  since  1914  and  foursince 
1915.  The  HifH-9  sp.  within  one-half  mile  of  all  the  plantings  were  inspected  in  the 
autumn  of  1910.  Dim>ased  HH>en  sp.  were  foumi  around  two,  only.  These  were  two 
of  the  four  which  had  shown  diseased  trees  in  the  spring.  In  both  cases  cultivated 
varieties  of  KiheM  still  existed  within  five  hundred  feet.  It  seems,  therefore,  that 
th«'  n-moval  of  diseased  trec*s  and  all  currants  and  gooselK^rrios  within  five  hundred 
fe«*t  of  the  plantings  has  prc\Tnted  the  establishment  of  Cronartium  ribicola  in 
these  an*as. 

Citrwt  canker  invcntigationn  at  the  Florida  Tropical  lAiboratory,     R.  A.  Jbhlb 

S<}rne  cultural  charuct'*ristirtt  of  the  canker  organism,  Pseudamonas  Citri  Haase 
(Migula'rt  genuH)  or  liactrrium  (*itri  (Crohn's  genus  Bacterium  as  emended  by  Smith) 
are  as  follows:  (trowth  f>n  standard  agar  abundant,  spreading,  raised,  smooth, 
glistening,  transluscent,  pale  >-ellow,  viscid,  with  characteristic  odor  in  about 
6%^  days.  Vitality  ten  to  thirty  day's,  (trowth  on  |M>tato  agar  more  abundant 
and  spn*adtng  with  lighter  color.  Growth  on  potato  slices  more  viscid  and  brighter 
>tIIow  with  fiifltinrt  white  margin  on  |K)tato  adjaoi*nt  to  culture.  White  margin 
l»ecomes  wry  pn>mim*nt  in  forty-eight  hours  and  do«>s  not  stain  with  iodine.  On 
gra|M*fruit  leaf  and  st4*ni  decoction  agar  slants  grom'th  |Nrnet rates  the  agar  and  if 


1917]  New  York  Meeting  59 

less  raised.   On  oat  agar  slants  growth  is  much  more  spreading  and  the  color  is  much 
lighter. 

Positive  results  have  been  obtained  from  inoculations  on  grapefruit,  ponderosa 
lemon,  key  lime,  Citrus  trifolicUOf  sour  orange,  tangelo,  sweet  orange,  tangerine, 
king  orange,  mandarin-lime,  and  kumquat.  Disease  also  occurs  on  navel  orange, 
mandarin,  satsuma,  conmion  lemon,  rough  lemon,  and  Aegle  glutinoaa. 

Studies  upon  the  anthracnose  of  the  onion.    J.  C.  Walker 

A  morphological  study  of  the  causal  organism  Colletotrichum  circinans  (Berk.) 
Vogl.  shows  the  fruiting  body  to  be  an  acervulus  and  not  a  pycnidium  as  first  de- 
scribed by  Berkeley,  confirming  the  findings  of  Voglino  who  transferred  the  fungus 
from  the  genus  Vermicularia  to  Colletotrichum.  Further  study  has  shown  it  to 
conform  closely  to  the  description  of  Colletotrichum  fructum  (S.  &  H.)  Sacc.  {Volutella 
fructi  S.  &  H.),  reported  by  Stevens  and  Hall  as  causing  a  fruit  rot  of  apple.  Inocu- 
lation of  the  fungus  from  onion  into  apple  fruits  resulted  in  a  rot  very  similar  to 
Volutella  rot.  Further  study  is  necessary  before  the  two  fungi  can  be  considered  as 
identical. 

Inoculation  of  onion  bulbs  in  soil  held  at  different  temperatures  shows  best  in- 
fection to  take  place  between  24**  and  29**C.  This  may  account  in  part  for  the  rather 
sparing  appearance  of  the  disease  until  shortly  before  harvest.  The  fungus  over 
winters  in  the  soil  and  consequently  the  disease  is  most  severe  on  old  onion  fields. 

Spraying  the  bulbs  before  harvest  or  in  the  crates  after  harvest  has  not  proved 
beneficial.  The  fact  that  yellow  and  red  varieties  of  onion  are  highly  resistant 
offers  some  encouragement  for  the  development  of  a  resistant  white  strain.  Work 
in  this  direction  is  to  be  continued. 

Pink  root,  a  new  root  disease  of  onions  in  Texas.  J.  J.  Taubenhaus  and  A.  D.  Johnson 
A  new  disease  known  as  pink  root  is  causing  serious  losses  to  onion  growers  of 
Webb  County,  Texas.  The  trouble  seems  to  prevail  only  where  onions  are  grown 
for  two  3rears  or  longer  on  the  same  land.  The  same  is  also  true  for  the  seed  bed 
where  the  same  old  soil  is  used  for  several  3rears  in  succession.  The  disease  starts 
with  the  young  sets  in  the  seed  bed  and  from  there  is  carried  to  the  field. 

The  roots  of  the  affected  sets  in  the  seed  bed  or  the  plants  in  the  field  turn  pink 
in  color  then  strivel  and  die.  As  fast  as  new  roots  are  formed  they  become  infected, 
turn  pink  and  dry.  The  effect  of  pink  root  is  to  prevent  the  normal  development 
of  the  bulbs  in  the  field  and  to  produce  dwarfed  undersized  bulbs  which  are  absolutely 
worthless  as  far  as  the  market  is  concerned.  The  cause  of  the  disease  is  still  proble- 
matic. Attention  is  called  to  it  at  this  time  because  of  its  great  economic  impor- 
tance to  Texas  onion  growers.  Extensive  investigations  are  now  under  way  to 
determine  the  cause  and  possible  remedies  for  this  disease. 

Two  new  camphor  diseases  in  Texas.    J.  J.  Taudenhaus 

Two  new  or  little  known  diseases  seem  to  threaten  the  existance  of  camphor 
trees  in  Texas : 

1.  Anthracnose.  The  fungus  attacks  and  kills  the  leaves  and  branches.  Affected 
trees  have  a  defoliated  appearance  at  the  top.  The  cause  of  the  trouble  is  apparently 
a  new  species  of  Glceosporium  tentatively  named  Olasosporium  camphorcB.  The 
organism  is  readily  grown  in  pure  culture  and  the  disease  reproduced  at  will. 

2.  Limb  canker.  This  disease  is  characterized  by  a  dying  of  the  larger  limbs  to 
about  four  to  six  fe^t  from  the  top.  The  limbs  turn  dark  and  soon  shed  their  leaves. 
Affected  trees  have  a  ragged  and  burned  appearance .    A  fungus  of  the  genus  Diplodia 


60  Phytopathology  [Vol.  7 


is  &lwa3r8  aasociated  with  this  disease.  Investigations  are  now  under  way  to  de- 
termine whether  this  Diplodia  is  the  same  or  similar  to  D,  Campkorm  F.  Taaai, 
occurring  in  Italy,  and  whether  also  it  is  the  direct  cause  of  the  disease.  A  full 
description  of  the  two  organisms  will  appear  at  a  later  date. 

Common  and  Bcientifie  name*  of  plant  dUeaiti,    M.  B.  Waits 

Common  names  of  plant  diseases  are  used  by  a  larger  number  of  people  than 
scientific  names.  Pathologists  should  encourage  the  movement  to  make  oommon 
names  definite  and  national.  By  being  made  definite  they  can  attain  their  proper 
status  in  discussions,  literature,  dictionaries,  quarantine  regulations,  laws,  and 
legal  proceedings.  By  agreement  among  pathologists  they  may  even  become  more 
fixed  than  scientific  names. 

There  may  be  four  distinct  names  connected  with  every  parasitic  disease;  the 
oommon  name  of  the  disease,  the  scientific  name  of  the  disease,  the  common  name 
of  the  parasite,  the  scientific  name  of  the  parasite.  For  example:  lemon  scab. 
Verrucosis,  lemon  scab  fungus,  Cladosporiwn  Cilrx.  In  case  of  all  common  diseaeee 
the  aim  should  be  to  provide  these  four  names.  Confusion  has  resulted  in  the  fail- 
ure to  recognise  these  four  kinds  of  names,  particularly  in  the  use  of  the  scientific 
name  of  the  disease  and  the  scientific  name  of  the  fungus  as  the  common  name  of 
the  disease.  Scientific  names  may  become  conmion  names  through  use  but  these 
cases  should  be  clearly  recognised  as  such  and  avoided  if  possible  and  vacancies  in 
names  also  recognised. 

Nonparasitic  diseases  may  have  two  names,  common  and  scientific,  and  the  same 
principles  apply. 

Economic  HomU  of  Sclerotinia  libertiana  in  tidewater  Virginia,  J.  A.  McClintock 
The  warm,  humid  climate  of  tidewater  Virginia  is  especially  favorable  to  the 
development  of  ScUrotinia  libertiana.  This  fungus,  long  known  as  a  serious  parasite 
on  lettuce,  has  been  observed  to  destroy  over  fifty  per  cent  of  the  autumn  lettuce 
crop  on  farms  where  no  rotation  is  used.  In  the  fall  of  1915  a  serious  disease  of  snap 
beans  due  to  this  organism  was  found.  During  the  winter  of  1915-1916  Sclerotinia 
libertiana  was  found  to  be  the  cause  of  a  fruit  rot  of  tomato  in  the  greenhouse.  In 
winter-grown  parsley,  under  sashes,  this  fungus  in  one  case  caused  drop  of  ten  per 
cent  of  the  crop  in  the  infected  frames.  Sclerotinia  libertiana  caused  the  damping 
off  of  a  large  proportion  of  the  seedling  plants  in  several  cold  frames  of  cauliflower 
being  raised  for  a  spring  crop  of  1916.  In  the  summer  of  1916  this  fungus  caused  a 
stem  blight  of  liearing  egg  plants,  on  several  farms.  In  each  case  the  writer  was 
able  to  isolate  the  causal  organism  and  to  reproduce  the  disease  in  the  respective 
hosts,  and  in  other  hosts  by  cross  inoculation. 

Lima  Itran  monaic.     J.  A.  McClintock 

During  the  summer  of  1916  while  conducting  experiments  with  nine  varieties  of 
pole,  and  s(*\'en  varietieif  of  buith  lima  Iwans,  the  writer  observed  a  serious  mosaie. 
It  wait  olMier\'ed  first  on  the  Sieva  pole  lima  or  butter-l)ean  and  later  on  Improved 
Hendenwm'ii  Biuih  and  Prolific  bush,  lima  lieans  of  the  Sieva  type. 

Owr  twenty-five  per  cf»nt  of  the  several  hundred  plants  of  each  of  the  above- 
mentioned  varieties  wen*  stunted  and  l>ore  the  dwarfed,  mottled,  wavy  leaves,  ehar^ 
actertstic  of  this  mosaic.  None  of  the  varieties  of  larger  limas,  which  made  up  the 
remainder  of  the  planting.  showiMl  signs  of  this  mosaic,  though  they  were  grown  under 
the  same  conditions  and  in  many  cases  intertwined  with  the  mosaic  diseased  plants 


1917]  Nbw  York  Meeting  61 

of  the  Sieva  type.  Lima  beans  had  not  been  grown  on  this  land  previously  and  no 
beans  of  this  type  were  Rowing  nearby,  therefore,  it  was  concluded  that  this  lima 
bean  mosaic  was  carried  by  the  seed.  This  disease  is  serious  because  the  yield  on 
the  infected  plants  is  greatly  decreased  and  the  pods  are  smaller  and  malformed. 

Bean  mosaic.    V.  B.  Stewart  and  Donald  Reddick 

Hundreds  of  acres  of  pea  beans  (Phaseolus  vulgaris)  in  New  York  showed  the  mosaic 
disease  in  1916  and  in  some  fields  practically  every  plant  was  afifected.  Affected 
plants  rarely  set  pods.  The  disease  is  not  confined  to  pea  beans.  Numerous  other 
varieties  of  dry  and  snap  beans  showed  the  disease  but  not  so  commonly  as  pea  beans. 

The  mosaic-diseased  leaves  on  affected  bean  plants  show  irregular  crinkled  areas, 
somewhat  deeper  green  in  color  than  the  surrounding  3rellowish  green  tissue.  The 
disease  is  transmitted  through  the  seed.  Bean  seed  from  mosaic-diseased  plants 
developed  diseased  seedlings.  Healthy  seedlings  rubbed  with  crushed  mosaic-dis- 
eased leaves  showed  infection  four  weeks  later.  The  first  signs  of  the  disease  ap- 
peared in  leaves  which  developed  about  blossoming  time.  Leaves  which  had  de- 
veloped previously  remained  healthy.  High  temperature  |knd  humidity  at  time  of 
inoculation  slightly  favor  infection. 

Two  transmissible  mosaic  diseases  of  ctxumbers,    Ivan  C.  Jagger 

In  Phytopathology  for  April,  1916,  there  is  a  group  of  articles,  dealing  with  a 
mosaic  disease  of  cucumbers,  commonly  known  as  white  pickle,  which  causes  a  mot- 
ling  of  both  leaves  and  fruits.  In  the  vicinity  of  Rochester,  New  York,  there  occurs 
a  second  and  distinct  mosaic  disease,  which  exhibits  a  mottling  of  the  leaves,  but 
shows  no  effect  on  the  fruits.  The  latter  disease  has  been  repeatedly  transmitted  to 
healthy  plants  by  rubbing  with  crushed  diseased  leaves,  and  has  been  transmitted 
to  muskmelons  and  to  summer-crookneck  squashes.  This  may  be  the  disease 
observed  by  Selby  in  Ohio  and  by  Stone  in  Massachusetts. 

Bean  diseases  in  New  York  State  in  1916.    W.  H.  Burkholder 

An  investigation  of  the  diseases  of  the  field  bean  in  western  New  York  begun  in 
1915  was  continued  during  the  summer  of  1916.  The  most  serious  disease,  a  dry 
root  rot,  caused  by  a  species  of  Fusarium,  was  reported  last  year.  Morphologically 
the  pathogene  is  nearly  identical  with  Fusarium  Martii  Ap.  and  Wr.,  although 
infection  was  not  obtained  by  inoculation  with  the  latter  fungus.  The  organism 
winters  over  in  manure  where  bean  straw  has  been  used  as  feed,  and  thus  may  be 
spread  from  field  to  field.  There  is  also  evidence  that  the  fungus  may  live  for  many 
years  in  the  soil.  The  disease  was  foimd  in  practically  all  of  the  one  hundred  and 
fifty  fields  visited  in  western  New  York.  Apparently  all  varieties  of  beans  are 
equally  susceptible  to  the  disease  although  certain  undesirable  types  of  the  white 
marrow  are  very  resistant.  A  few  individuals  of  these  have  been  selected  for  breed- 
ing stock. 

The  blight,  caused  by  Bacterium  Phaseoliy  and  the  mosaic  along  with  dry  weather 
also  aided  in  reducing  the  bean  crop  of  1916.  There  is  some  indication  that  Bac- 
terium Phaseoli  causes  a  stem  girdling.  Anthracnose  was  destructive  in  1915,  but 
caused  little  damage  in  1916. 

Do  the  bacteria  oj  angular  leaf  spot  of  cucumber  overwinter  on  the  seed?    Eubanks 

Carsner 

This  question  was  first  suggested  by  the  writer's  observation  in  June,  1915,  of 
the  occurrence  of  angular  leaf  spot  in  a  field  on  recently  cleared  land  surrounded 


6i  Phytopathology  [Vol,  T 

bj  woods  near  Portsmouth,  Virginia.    This  field  was  removed  at  least  three  or  four 
miles  from  any  other  cucumber  patch. 

In  1916  near  Madison,  Wisconsin,  six  separate  experimental  fields  were  planted 
with  seed  from  the  same  source  on  land  which  had  not  been  planted  to  cucumbers 
for  at  least  three  years.  The  disease  appeared  on  seedlings  in  all  of  these  fields  and  • 
in  three  of  them  it  was  noted  on  the  cotyledons.  In  three  commercial  fields  in  the 
same  vicinity,  planted  with  seed  from  other  sources,  the  disease  did  not  appear 
at  all  in  one  case  and  not  until  late  in  the  season  in  the  other  two. 

The  fart  that  angular  leaf  spot  appeared  on  seedlings  only  in  the  six  fields  planted 
with  seed  from  the  one  source  and  not  in  the  other  fields  in  the  vicinity  furnishes 
the  basis  for  the  working  hypothesis  that  the  causal  organism  is  seed-borne,  and  is 
oppo8C<i  to  the  theory  of  local  overwintering  of  the  organism  by  means  of  insects  or 
plant  debris. 

Infrrte<l  cucumber  fruits  in  considerable  numbers  have  been  seen  by  the  writer 
in  seed  fields.  The  method  of  securing  and  cleaning  the  seed  affords  ample  oppor- 
tunity for  the  organisms  to  reach  the  see<l,  and  the  process  includes  no  operation 
that  would  be  likely  to  |^ill  all  of  the  bacteria. 

Prelimiuary  notcn  on  n  ttetr  leaf  np<tt  of  cucumhern.     (Iko.  A.  Osnkr 

During  the  8oa.'<ons  of  1915  and  1910.  the  writer's  attention  was  called  to  a  peculiar 
leaf  spot  on  ruruinbcrH  that  was  raiising  more  or  leH.*<  damage  in  a  number  of  fields. 
The  sp<»t8  variwi  from  two  tenths  to  fiftt»en  millimeters  in  diameter,  the  majority 
of  the  smaller  spots  ranging  from  on<'  to  two  millimeterH  and  being  limited  in  most 
cases  by  the  veins  of  the  leaf.  The  larger  spots  were  white  or  tingcxi  with  brown 
and  with  rcnldish  brown  areas  along  th<'  veins  of  the  leaf  which  gave  the  sjMits  a 
chararteristir  mottleil  appearance. 

The  dinea^e  was  found  to  be  due  to  a  fungus  belonging  to  the  DematiaceavDictyo- 
spone  group  of  the  Hyphomyretes.  Its  exact  generic  position  has  not  been  deter- 
mineti  a.**  yet.  The  <irganisni  was  securcnl  in  pure  culture  on  string  bean  agar  and 
8uc<'e*«sful  inorulntions  have  been  made  on  young  cucumber  plants  in  the  green- 
house, the  rherkM  remaining  healthy  in  all  eases. 

ViruUncf  of  Hiffrrrut  ntraiuH  of  CUuiosporium  ciwumrrinum.     W.  W.  GiLBEKT 

\  considerable  number  of  strains  of  the  cucumber  scab  fungus,  Cladonporium  cm- 
cumrrinutn.  have  been  isolatiNl  from  cucumber  fruits  from  different  localities  and 
grown  in  culture,  and  many  series  of  inoculation  experiments  have  IxH'n  mmle  tm 
sei*<llings  and  young  and  old  plants.  It  has  been  found  that  these  strains  vary 
widely  in  their  ability  to  infect  cucumber  plants.  Some  have  failtnl  to  prcnluce 
any  infertion  after  many  trials,  while  others  are  uniformly  virulent.  One  strain 
in  partifiilar  liaj*  ^iven  very  striking  infection  practirally  I'very  time  when  favorable 
conditionM  were  maintain***!.  The  virulent  strains  attack  cotyle<lons  and  stems  of 
young  cucumber  ^e<Nllings  in  inoi.st  chamlxTs  and  kill  them  in  two  to  four  days. 
They  also  attack  and  kill  vtTy  rapidly  the  younger  leav(*s,  stems  and  growing  tips 
of  larger  iilants  under  favorable  moisture  conditions.  I'nder  identical  conditions 
the  iionvirulent  strains  faihsi  to  prcnluce  infection.  Similar  results  were  secured 
when  youiiK  cucunib<>r  fruits  were  inoculated  in  moist  cluunbers  with  different  strain* 
of  (*lado^|M>rium. 

Ihfntmxuotiitu  ♦»/  Ihr  nrgnninm  of  rurumher  anlhracnone .     M.  \V.  GARDNER 

In  A  fairly  large  acreage  of  cucumbers  and  other  cucurbits  under  observation 
in  19HV  the  ap|M*arance  of  original  centers  of  anthracnose  in  only  the  plots  or  fields 


1917]  New  York  Meeting  63 

planted  with  seed  from  certain  sources  pointed  suspiciously  toward  disease  intro- 
duction with  the  seed.  Subsequent  inspection  of  seed  farms  revealed  the  presence 
of  anthracnose  on  seed  fruits  and  that  the  processes  involved  in  seed  extraction  may 
furnish  efifective  means  of  seed  contamination. 

Extensive  spread  from  original  centers  of  infection  in  the  cucumber  fields  under 
observation  followed  periods  of  heavy  rainfall.  The  principal  direction  of  spread 
was  that  of  the  surface  drainage.  Plate  isolations  of  the  fungus  were  made  from  soil 
near  diseased  plants.  Rows  of  healthy  seedlings  exposed  to  drainage  water  in  dis- 
eased fields  during  heavy  rains  the  first  week  of  September  became  abundantly 
infected  and  many  seedlings  were  killed  outright. 

Glass  tumblers  were  sunk  in  the  ground  at  various  points  in  two  fields  to  intercept 
surface  drainage  during  rains.  A  successful  plate  isolation  of  the  fungus  was  made 
from  water  thus  collected.  Samples  collected  in  one  field  after  rains  on  Septem- 
ber 5  and  in  the  other  field  after  rains  on  September  12,  when  sprayed  or  sprinkled 
on  healthy  potted  cucumber  plants,  produced  numerous  anthracnose  lesions. 

A  bacterial  stem  and  leaf  disease  of  lettuce.    Nellie  A.  Brown 

A  serious  stem  and  leaf  disease  of  lettuce  appeared  in  Beaufort  County,  South 
Carolina,  1916.  The  disease  occurred  chiefly  on  two  plantations,  one  of  seven- 
teen, the  other  of  nine  acres;  a  conservative  estimate  of  loss  on  the  former  was  sixty 
per  cent;  on  the  latter  ninety  per  cent.  Other  plantations  within  a  radius  of  twenty 
miles  suffered  one  to  ten  per  cent  loss. 

The  affected  plants  were  wilted,  the  outer  leaves  blotched  and  darkened.  Rot- 
ting was  often  rapid.  A  cross-section  of  stem  at  an  early  stage  of  disease  showed 
a  blue-green  color;  later  stage,  brown.  Both  pith  and  vascular  regions  were  in- 
volved. Later  the  stem  usually  became  dry  and  brittle.  Moderately  diseased 
plants  are  darkened  in  patches  in  stem,  and  vascular  region.  Bacteria  filled  the 
cells  of  the  blue-green  and  brown  areas.     No  fungi  were  found. 

A  bacterial  organism  was  isolated  which  when  inoculated  into  lettuce  produced 
the  blue-green  color  throughout  the  vascular  system  and  pith,  which  later  became 
brown.  Disease  appeared  on  leaves  also.  Eight  months  after  isolation  this  or- 
ganism, which  is  yellow  on  various  media  and  is  doubtfully  motile,  is  still  infectious. 
In  its  morphological  and  cultural  characters  it  does  not  correspond  with  any  or- 
ganism recorded  as  pathogenic  to  lettuce. 

Blajck  spot  of  pepper.    L.  E.  Melchers  and  E.  E.  Dale 

In  1915  a  striking  pathological  condition  of  fruits  of  peppers  was  noticed;  the 
disease  ranging  as  high  as  45  per  cent.  A  species  of  Altemaria  has  been  consistently 
associated  with  diseased  areas.  These  are  slightly  sunken,  dark  colored  and  not 
confined  to  any  particular  location.  Inoculations  show  that  the  organism  is  only 
a  weak  pathogene  when  inoculated  into  normal  tissue.  When  the  pericarp  is  me- 
chanically (slightly)  injured,  the  fungus  becomes  established  and  diseased  areas 
enlarge.  There  are  apparently  two  ways  or  combinations  of  factors  in  which  natural 
injuries  may  occur  to  peppers  in  the  field;  (1)  injured  areas  from  sun-scald,  (2)  frost 
injuries.  Artificially  injuring  the  pericarp  by  means  of  a  burning-glass  and  apply- 
ing the  fungus  superficially,  produces  a  condition  which  is  the  counterpart  of  the 
symptoms  occurring  in  the  field.  Varietal  resistance  is  shown  by  the  data  of  1916. 
Sweet  peppers  are  more  susceptible  than  the  hot  varieties.  Among  15  varieties 
grown,  the  percentage  of  disease  ran  from  0.02  to  2.7  among  hot  peppers  and  from 
0.4  to  23.07  among  the  sweet  ones,  with  an  average  of  13.6  among  the  latter  when 
sprayed  and  11.7  in  the  unsprayed.  Bordeaux  sprays  do  not  control  the  malady. 
Affected  fruit  is  unsalable. 


64  Phytopathology  [Vol.  7 

A  9cUrotium  dUeoMe  of  pepper$.    Wiluam  H.  Martin 

The  disease  is  characterised  by  the  presence  of  numerous,  minute,  blaek  sclerotia 
throu|(hout  the  fruit  as  well  as  on  the  seeds.  With  the  exception  of  a  blackening 
of  the  epidermis,  the  disease  may  pervade  the  entire  interior  before  any  external 
symptoms  are  noticed. 

The  fungus  was  isolated  and  grown  in  pure  culture.  The  pathogenicity  of  the 
fungus  has  been  fully  established  by  numerous  successful  inoculations  on  both 
green  and  ripe  fruit,  as  well  as  on  the  plant  itself,  and  by  the  subsequent  re-isola- 
tion in  pure  culture.  Reinoculations  with  this  second  isolation  again  produced 
the  typical  rot. 

The  identity  of  the  pathogene  has  not  been  satisfactorily  determined  but  there 
is  evidence  for  the  belief  that  it  is  ScUrotium  bataticola  Taubenhaus. 

Successful  cross  inoculations  have  been  made  on  pepper  and  sweet  potato  as  well 
as  on  cucumber,  tomato,  apple  and  egg  plant. 

DiMfffiifui/t on  of  Bacterium  hfalvacearum,     R.  C.  Faulwetter 

Through  investigations  of  the  means  by  which  Bacterium  hfalpacearum  may  be 
disseminated,  it  has  been  concluded  that  wind  during  rainfall  is  the  most  impor- 
tant agent.  Neither  insects  nor  seed  infection  can  account  for  the  prevalance  of 
the  angular  leaf  spot  caused  by  it  in  all  varieties  of  cotton.  An  inoculation  experi- 
ment consisting  of  one  row  of  plants  in  a  field  free  of  the  disease  was  followed  within 
a  month  by  infection  of  the  plants  to  the  east  as  far  as  the  fourteenth  row,  and  in 
the  next  month  by  the  spread  of  the  disease  to  the  west.  A  second  experiment  ar- 
ranged and  operating  during  the  second  month  also  showed  spread  to  the  west. 
Practically  no  disease  occurred  east  or  west  of  uninfected  plants  in  the  original 
rows. 

It  was  demonstrated  experimentally  that  the  leaf-surface  film  during  heavy  dews 
contained  viable  bacteria.  It  is  to  l>e  expected  these  organisms  will  be  present 
during  rains.  Westerly  winds  prevailed  during  the  rains  at  the  time  the  disease 
spread  to  the  east,  and  during  the  next  month  the  wind  direction  had  changed,  blow- 
ing from  the  south-east.  Considering  the  slight  disease  opposite  the  uninoculated 
plants,  and  the  simultaneous  change  of  wind  direction  and  the  spread  of  the  dis- 
ease, it  is  held  that  wind  during  rainfall  is  the  most  active  agent  in  the  dissemina- 
tion of  the  causal  organism. 

• 
Bacterial  dineaseM  of  celery.     W.  8.  Kroitt 

These  diseases  occur  in  a  region  with  a  deep  muck  soil  and  a  very  humid  climate. 

Trotrn  rot.  This  disease  is  prevalent  in  the  greenhouses  and  fields.  The  symptoms 
are  a  yellowing  of  the  foliage  and  a  rotting  of  the  crown  starting  through  side  roots. 
Plants  arc  destroye<l  in  fnim  three  to  four  wcekn  after  infection.  The  causal  organ- 
isms appear  to  l>e  a  Bacterium  and  a  Fui«ariiim  working  simultaneously.  Steam 
steriliiation  and  the  following  rhemimls  have  lieen  applied  in  varying  amounta  to 
the  soil  for  the  control  of  the  disease:  foniialin,  calcium  chloride,  copper  sulphate, 
ferrous  sulphate,  sulphur,  scMliuni  chloride  and  potash. 

Crown  rot  trilt.  This  diHoasc  is  intermittent  in  its  orrurrence.  It  is  characterised 
by  a  sudden  wilting  of  the  entire  foliage,  an  oval  hollow  cavity  in  the  crown  and  a 
ba<ily  difM*ased  tap  r(N>t  which  hitvi^s  as  a  channel  of  inf«*ction. 

Bacterial  heart  wilt.  The  bacteria  attack  only  the  innermost,  tender  leaves  caus- 
ing a  wet,  carlKtnaceoiiH  rot.  The  organism  has  l>een  isolated  and  its  pathogenicity 
proved. 


1917]  New  Yobk  Mseting  65 

A  bacterial  blight  of  say  bean.    A.  G.  Johnson  and  Florence  M.  Coebpbb 

For  a  number  of  years  this  disease  has  been  under  investigation  at  Madison,  Wis- 
consin. A  malady  apparently  the  same  has  also  been  reported  from  other  parts 
of  the  United  States.  At  Madison  the  disease  has  been  common  during  the  past 
three  years,  especially  on  the  leaves. 

These  leaf  lesions  are  small,  rather  angular  spots,  in  late  stages,  dark  in  color, 
brown  to  purplish  black.  In  the  earlier  stages  they  are  translucent  and  water  soaked 
in  appearance  and  yellowish  to  light  brown  in  color.  The  lesions  may  be  irregularly 
scattered  or  variously  grouped  and  they  not  uncommonly  coalesce.  Rather  incon- 
spicuous glistening  films  of  exudate  are  frequently  noticeable  on  the  lowfr  surfaces 
of  the  lesions. 

Repeated  isolation  cultures  have  yielded  a  characteristic,  white  bacterial  or- 
ganism which  has  proved  pathogenic  on  soy  bean,  producing  characteristic  lesions 
as  described  above.  The  same  organism  has  been  reisolated  from  such  lesions  and 
its  pathogenicity  in  turn  proved.  This  organism  is  a  rod  with  rounded  ends,  motile 
by  a  single  polar  flagellum,  hence  referable  to  the  genus  Pseudomonas  of  Migula 
or  the  genus  Bacterium  of  Ehrenberg  as  interpreted  by  Erwin  F.  Smith. 

Studies  on  the  physiological  characteristics  of  the  organism  and  its  pathogenicity 
on  other  leguminous  hosts  are  in  progress. 

Host  limitations  of  Septoria  Lycopersici.    J.  B.  S.  Norton 

Inoculations  of  seedlings  of  a  number  of  Solanaceae  and  eighty  varieties  of  tomato 
in  humid  enclosures,  with  Septoria  from  tomato  resulted  in  infections  on  several 
species  of  Solanum,  eggplant,  Datura  tatttkif  and  especially  on  potato,  currant  tomato 
and  Solanum  carolinense.  Spots  developed  better  and  spores  larger  on  potato  and 
horse-nettle  than  on  tomato,  while  the  Datura  spots  were  slow-growing,  light  colored 
and  small-spored.  With  larger  plants  outdoors,  infections  appeared  rarely  except 
on  Lycopersicum ;  but  undoubted  infections  resulted  on  horse-nettle  and  potato 
and  occasional  pycnidia  developed  with  spores  smaller  than  on  tomato.  The  to- 
mato varieties  in  the  seedling  stage,  showed  decided  differences  in  susceptibility 
to  the  Septoria,  both  in  number  of  infections  and  time  of  development.  Many 
dwarf  varieties  showed  marked  susceptibility. 

Wintering  of  Septoria  petroselina  var.  Apii.    W.  S.  Krout 

Heretofore,  the  seed  has  been  considered  the  primary  source  for  dissemination 
and  wintering  of  this  organism.  The  following  observations  and  results  of  tests 
indicate  this  is  not  the  case:  (a)  Pycnidia  with  spores  are  found  on  the  pedicles 
and  have  been  reported  on  seed,  (b)  All  spores  taken  from  the  dried  pedicles 
failed  to  germinate,  (c)  Spores  from  green  celery  tissues  subjected  to  dessication 
for  eight  months  under  laboratory  conditions  failed  to  germinate,  (d)  Young 
seedlings  in  the  seed-bed  were  never  infected  unless  planted  on  soil  that  had  pre- 
viously grown  celery  infected  with  this  organism,  (e)  This  organism  forms  sclero- 
tial-like  intercellular  bodies  in  the  petioles,  (f)  Celery  grown  in  new  localities 
gradually  becomes  infected,  (g)  Seed  from  the  same  bag,  but  divided  and  sown 
upon  two  different  farms  produced  the  diseased  seedlings  in  one  case  and  healthy 
seedlings  in  the  other. 

These  studies  indicate  that  the  disease  is  not  carried  in  the  seed  but  in  manures 
containing  diseased,  decomposed  plants,  and  probably  by  other  methods. 

Laboratory  work  has  shown  that  heating  celery  seed  to  50**C.  for  one-half  hour 
will  eliminate  all  chances  (if  there  be  any)  of  the  disease  being  disseminated  through 
the  seed  and  pedicles. 

Incomplete  studies  on  Cercospora  Apii  Fr.,  indicate  similar  conditions. 


66  Phytopathology  [Vol.  7 

A  nematode  disease  of  the  dasheen  and  iU  control  by  hot  water  treatment.     L.  P.  Btaks 

During  the  summer  of  1914,  a  new  disease  of  an  economic  aroid,  the  dasheen, 
Coiocasia  esculenta  (L.)  8chott,  waa  found  at  one  point  in  Florida  causing  serioua 
damage.  The  malady  is  caused  by  the  widely  distributed  nematode  or  eel  worm, 
Hcterodera  radicicola  (Grcef)  Moller,  which  causes  root-knot  of  many  wild  and  cul- 
tivated plantK,  but  which  has  not  heretofore  been  authentically  reported  on  the 
dashren.  In  some  places  it  has  caused  almost  a  complete  failure  of  the  dasheen 
crop  and  is  roffardcd  as  the  most  serious  pathological  factor  in  the  successful  pro- 
duction of  thiH  plant. 

The  dit4asp  has  been  found  on  dasheens  in  most  of  the  South  Atlantic  States  where 
€M*onoiiiir  aroids  arc  grown  and  in  a  shipment  of  cormcls  imported  from  Egypt  for 
propagating  pur]>08os. 

On  <lashcon  roots  the  nematode  produces  macroscopically  conspicuous  svi'cllings 
which  hinder  normal  absorjition.  On  the  surface  of  the  tuberous  growth  it  causes 
protuberances  and  definite  raiscMi  areas  resembling  open  sores,  through  which  s€M?ond- 
ary  hel<l  and  storage  parasites  may  readily  enter.  The  eelworm  docs  not  live  on 
the  aerial  parts  of  the  <lashet»n.  but,  in  rase  of  severe  infection,  it  causes  these  |>or- 
tions  to  be  greatly  r<HluriMl  in  size,  and  gives  to  the  plant  as  a  whole  a  decidedly  sickly 
app«'aranec\ 

The  disease  has  been  surressfully  controllcHl  by  planting  on  uninfecte<l  land  se- 
lected rormels  from  disrase-free  areas,  or  diseaswl  connels  which  have  been  treatetl 
with  water  at  o()°(\  for  forty  minutes. 

Sot*  worthy  }*orto  Rirau  plant  di^icaxcn.     V.  L.  ST*:vE.\rt 

To  U'  printed  in  full  in  thi*  April  issue  of  Phytofathouxjy. 

Suljuriruj  Concord  grnjHH  to  prevent  jHncdery  mildew.     F.  K.  CiLADWIN  and  Donald 

Hkoouk 

Continuing  work  rcfxirtcHl  in  Internat.  Cong.  Vit.  Off.  Kept.  1916:  117-12o.  1916, 
plats  of  Concord  grape  vines  were  duste<i  three  times,  July  18,  August  2  and  August 
16,  with  sulfur-Iinie  mixtures  containing  respectively  twenty-five,  fifty  and  seventy- 
five  percent  »iulfur  flour,  ninety-five  per  cent  or  more  of  which  pa-sses  'J(X)-mesh  sieve. 
The  mixtures  were  applieil  at  the  rate  of  forty  pounds  per  acre.  A  single  applica- 
tion of  liordeaux  mixture  was  made  <»n  one  plat  on  August  11.  Treatinl  plats  al- 
trrnuted  uith  rherk  plats  and  all  plats  were  separatnl  by  one  buffer  row. 

I*o\i<lerv  mildew,  causetl  bv  I'nrinula  neeator,  was  abundant.  At  harvest  time 
f»ne  untreat<Hl  plat  showetl  four  per  rent  of  the  rlusters  free  from  mildew  and  an- 
other only  tl.U()7  per  cent  fr<*e.  The  lM)rdraux-!<pray<'<i  vines  showi*<l  six  per  cent  of 
th<*  elu>«ti*rs  free  from  mildew,  the  mixture  rontaining  sfventy-five  per  cent  sulfur 
showeil  ninety-six  j)er«M*nt  frer.  that  containing  fifty  per  cent  showtn!  eighty-three 
per  cent  fr<*<*  and  that  containing  twenty-five  per  cent  sIiow^hI  twenty-seven  i>er 
cent  free.  The  seventy-five  per  cent  mixture  causi»<l  severe  burning,  the  fifty  per 
cent  mixture  a  small  amount  of  biiniing  and  the  twenty-five  per  cent  mixture  slight 
burning 

The  nrrial  triage  of  (\dtonfMtrium  elephiintoiHtdin.  (»Eo.  (I.  IlKUCK^tK'K  and  W.  H.  Ix)SO 
Voung  triM»s  of  l*\nuA  heterophylUi  in  the  greenhouse  at  Washington.  D.  C,  were 
in<HnilAti*d  under  cc»ntrolli*<i  conditions  in  November.  1915.  with  the  teliospores  of 
CtUrtn^fHtnum  flrphnntofMHiiM  (Schw./Thnm.  In  February,  1910.  the  aecia  of  Pcri- 
dermtum  carneum  {lUtBc.)  Seym,  and  Karle  appeareti  on  the  needles  in  abundance. 


1917]  New  York  Meeting*  67 

These  were  fully  mature  late  in  March.  Inoculations  with  the  aeciospores  March 
7  and  April  5,  1916,  on  the  leaves  of  plants  of  Elephantopus  tomentosus  L.  produced 
in  abundance  the  characteristic  uredinia  and  telia  of  Coleosporium  elephantopodia. 

During  the  past  three  years  parallel  sets  of  inoculations  of  plants  of  Vernonia 
on  the  one  hand  and  of  Elephantopus  on  the  other  with  the  aecia  of  Pertdermium 
carneum  from  a  number  of  species  of  pine  have  resulted  in  producing  Colesoporium 
vernonicB  B.  and  C.  on  the  former,  and  C.  elephantopodia  on  the  latter,  indicating  the 
identity  of  the  two  species. 

Pertdermium  carneum  is  now  reported  for  the  first  time  on  the  needles  of  Pinus 
carihcBa  Morel.,  P.  clausa  (Engelm.)  Sarg.,  P.  echinata  Mill.,  P.  glabra  Walt.,  P. 
heterophylla  (Ell.)  Sudw.,  P.  ponderosa  Laws.,  P.  rigida  Mill.,  P.  scopulorum  (En- 
gelm.) Lemm.,  and  P.  serotina  Michx. 

The  Peridermium  belonging  to  Coleosporium  ipomceoB,    George  G.  Hedgcock  and 

N.  Rex  Hunt 

Peridermium  ipomceoB  a  new  foliicolus  species  on  Pinus  echinata  Mill.,  P.  palus- 
tris  Mill.,  P.  rigida  Mill.,  and  P.  taeda  L.  is  described,  with  a  range  from  Pensylvania 
to  Florida  and  Texas. 

Plants  of  Ipomcea  lacunosa  L.,  /.  pandurata  L.,  /.  triloba  L.,  Pharbitis  barbigera 
(Sims.)  G.  Don.,  P.  hederacea  (L.)  Choisy,  and  Quamoclit  coccinea  (L.)  Moench  un- 
der controlled  conditions  were  successfully  inoculated  with  the  aeciospores  of  this 
Peridermium,  producing  on  their  foliage  the  typical  uredinia  and  telia  of  ColeospO" 
rium  ipom(EXB  (Schw.)  Burrill,  thus  proving  that  it  is  the  aecial  stage  of  this  Coleo- 
sporium. Plants  of  species  of  Amsonia,  Aster,  Calonyction,  Chrysopsis,  Convol- 
vulus, Coreopsis,  Elephantopus,  Helianthus,  Laciniaria,  Silphium,  Solidago,  Ver- 
besina  and  Vernonia  were  unsuccessfully  inoculated. 

Coleosporium  ipomcece  is  now  reported  for  the  first  time  on  the  leaves  of  Ipomolea 
caroliniana  Pursh.,  7.  trifida  (H.  B.  K.)  G.  Don.,  and  Pharbitis  barbigera, 

A   Peridermium   belonging  to  Coleosporium   terebinthinacece.    Geo.   G.  Hedgcock 

and  N.  Rex  Hunt 

Peridermium  terebinthinaceumf  a  new  foliicolus  species  on  Pinus  echinata  Mill., 
P.  rigida  Mill.,  and  P.  taeda  L.,  is  described  with  a  range  from  North  Carolina  to 
Georgia. 

Inoculations  were  made  under  controlled  conditions  with  the  aeciospores  of 
this  Peridermium  on  plants  of  Silphium  asteriscus  L.,  S.  intcgrifolium  Michx. ^  S.  tri' 
foliatum  L.  and  Parthenium  integrifolium  L.  in  May  and  June  1916.  In  about  two 
weeks  the  uredinia,  and  later  the  telia  of  Colesporium  terebinthinacea;  (Schw.) 
Arthur  appeared  on  the  leaves  of  all  these  species,  proving  the  Peridermium  to 
be  the  aecial  stage  of  this  Coleosporium.  Inoculations  were  made  at  the  same 
time  on  plants  of  species  of  Amsonia,  Coreopsis  and  Laciniaria  without  result. 

Coleosporium  terebinthinacece  is  now  reported  for  the  first  time  on  the  leaves  of 
Silphium  angustum  (A.  Gray)  Small,  S.  compositum  Michx.,  S.  dentatum  Ell.,  S. 
glabrum  Eggert,  and  S.  pinnatifidum  Ell. 

An  alternate  form  for  Coleosporium  helianthi.    George  G.  Hedgcock  and  N.  Rex 

Hunt 

A  new  foliicolus  species,  Peridermium  helianthi,  is  described  on  Pinus  virginiana 
Mill.,  with  a  range  from  Pennsylvania  to  South  Carolina  and  Tennessee.  Inocula- 
tions made  with  the  aeciospores  of  the  Peridermium,  under  controlled  conditions, 


Phytopathology  [Vol.  7 

on  planU  of  HelianthuM  decapetaluM  L,,  H,  divawieaiui  h,,  H.  ffiganteuB  L.,  H,  gla^mu 
Small,  and  H,  hir9utu9  Raf .  produced  the  uredinia  and  telia  of  CoUo^porium  kelianiki 
(Schw.)  Arthur,  usually  in  abundance,  thus  proving  the  Peridermium  to  be  the 
aecial  at  age  of  this  Ck>leo8poriunk.  Inoculations  were  made  at  the  same  time  on 
plants  of  species  of  Aster,  Chrysopsis,  Coreopsis,  Elephantopus,  Laciniaria,  Parthe- 
nium,  Rudbeckia,  Silphium,  Solidago,  Verbesina,  and  Vcmonia  with  negative  re- 
sults. The  results  of  these  inoculations  indicate  that  the  Coleosporiums  on  Coreop- 
sis and  Verbesina  arc  distinct  from  the  one  on  Helianthus.  The  Coleoeporium  in 
Florida  on  Verbesina  which  has  been  assigned  to  C.  heliarUki  may  belong  to  one  of 
the  unnamed  species  of  Peridermium  found  by  the  writers  in  the  south. 

CoUo9ponum  heliantki  is  now  reported  for  the  first  time  on  HelianthuM  au9traii9 
Small,  //.  divaricatus  L.,  //.  eggeriii  Small,  //.  glaucus  Small,  H.  gro99€'9erraiu9 
Martens,  //.  hirsutus  Raf.,  //.  microcephalus  T.  and  G.  ,and  //.  aaxicola  Small,  and 
its  range  (on  Helianthus)  is  extended  to  Louisiana  and  Florida. 

SoffM  fi^tr  ha$U  for  CoUo9parium  »olidagin%$.    Georqe  G.  Hedocock  and  N.  Rxx 

Htnt 

Peridermium  acirolum  I'ndcrw.  and  Earlc,  the  aecial  stage  of  CoUoBpcrium  coli- 
daginia  (Schw.)  Tht'im..  is  reported  for  the  first  time  on  Pinun  carihaea  Morel.,  P. 
coniarta  Loud..  P.  diraricata  (Ait.)  Du  Mont  do  Cours,  P.  echinata  Mill.,  P.  tUioltii 
Kngolm.,  P,  mayriana  Sudw.,  P.  nigra  Arnold  (P.  laricio  Poir.),  P.  nigra  var.  ays- 
iriaca  Srhneid.,  P.  jtaluatria  Mill.,  P.  ptpnderoaa  Law8.,  P.  acopiUarum  (Engelm.) 
liPmm.,  P.  nrrotina  Mirhx.,  P.  taeda  L.,  and  P.  thunhergii  Pari. 

Positive  results  have  been  obtained  from  inoculationfl  with  the  aeriospores  of 
Peridermium  acirolum  on  plants  of  species  of  Aster  and  Solidago,  and  negative  re- 
sults only,  on  plant**  of  Hpc*cics  of  Campanula,  ConvolvuluK,  Coreopsis,  Elephanto- 
pus, Kupat<irium.  Euthaniia,  Helianthus,  Ip<>nH>ea,  Laciniaria,  Parthcnium,  Phar- 
bitiK.  iS'iH'i'id.  Verbesina.  and  Vcmonia.  A  Coleosporium  on  Chrytopaia  mariana 
(L.)  Ntitt..  found  firMt  by  \V.  H.  Ixing  in  Florida,  in  tentatively  assigned  to  this 
sperics. 

The  range*  of  the  Peridermium  has  be<»n  cxtendwi  to  include  nearly  all  States  from 
Minnesota  and  New  Hampshire  on  the  north  to  Arkansa.H  and  Florida  on  the  south. 

Sotrf  on  name  tijterirn  of  ColroafMtrium.  (iKr>K(2K  (i.  HKDttriK'K  and  N.  Rkx  Hunt 
ColronjHtrium  delicatulum  .\rth.  and  Kern  is  report (h1  for  the  first  time  on  Euthamia 
earoliniaua  (L.)  (ireene,  and  E.  leptorephala  (T.  and  (•.)  Greene,  and  Peridermium 
delicatulum  (.-Xrth.  and  Kern)  Ilfnlge.  and  l^uig  for  the  fir<«t  time  on  Pinua  tariteif 
Morel..  /•.  echinata  Mill..  P.  eUiottii  Engelm..  P.  hrUrophylla  (Ell.)  Sudw.,  P.  may- 
riana  Sudw..  P.  palimtrin  Mill..  P.  nigra  .\rnoM.  /*.  /tonderosa  Lawn..  P.  reainoaa 
Ait..  P.  Htrotina  Mirhx.,  ami  /'.  tarda  L..  and  the  range  of  the  spei*ii*s  is  greatly 
e\tend«l. 

CotfoffHtrium  laciniarnr  .Vrth.  i.M  reiM)rt<*<l  for  the  first  time  on  l^aciniaria  earlei 
(•reene.  L.  drgann  (Walt. )  Kuntze.  L.  ttongata  (tre<»ne,  L.  /xtuciflora  (Pursh)  Kuntie, 
L.  acariima  < L.  i  Hill,  and  L.  utrotina  (!re<>ne,  and  the  range  of  the  specie's  extended 
to  Klnridu  on  the  .^fiuth  and  to  New  Jersey  un  the  north. 

Some  ri«  1/  hit<*t)*  ftn  ('itl*tt*fmn turn  inritntpicuum.     (iKoHciK  (i.  Hk<iD<'<x*K  and  N.  Rex 

Hi  .ST 

Ac*<-io*>|Niri*s  fr«»ni  PiTxdtrmium  tnconapicuum  I^mg  rollert4*d  for  the  first  time  on 
the  nc4*4lles  of  Ptnuf  echtnata  Mill,  were  Huce<*ftsfully  inorulat<*d  on  the  leaves  of 


1917]  New  York  Meeting  69 

both  Coreopsis  major  omUeri  (Ell.)  Britton  and  C.  verticiUcUa  L.  resulting  in  the 
fonnation  of  the  uredinia  and  tellia  of  Coleosporium  inconspicuum  (Long)  Hedge, 
and  Long.  Unsuccessful  inoculations  were  made  on  plants  of  species  of  Amsonia, 
Aster,  Chrysopsis,  Elephantopus,  Euthamia,  Helianthus,  Laciniaria,  Silphium, 
Solidago,  Verbesina>  and  Vemonia.  The  results  of  these  inoculations  indicate 
that  Coleosporium  inconspicuum  is  distinct  from  species  found  on  plants  of  these 
genera.  This  Coleosporium  is  reported  for  the  first  time  on  Coreopsis  delphinifolia 
Lam.,  C  lanceolata  L.,  C.  major  Walt.,  C.  major  rigida  (Nutt.)  Boynton,  and  C. 
Iripteris  L. 

Coleosporium  apocynaceum  Cooke  has  been  collected  at  Clearwater,  South  Caro- 
lina on  Amsonia  cliate  Walt. 

• 
Scolecotrichum  graminis  on  timothy,  orchard  grass,  and  other  grasses.    A.  G.  John- 
son and  C.  W.  Hunoerford 

During  the  past  few  years  Scolecotrichum  graminis  has  been  observed  by  the 
writers  on  timothy  and  orchard-grass  at  various  points  from  Wisconsin  to  the  Pacific 
Coast.  The  fungus  causes  a  serious  disease  of  these  hosts  especially  in  Wisconsin. 
The  young  lesions  on  the  leaf  are  circular  to  elliptical  in  form,  vary  greatly  in  size, 
and  are  usually  purplish  brown  in  color,  The  older  lesions  turn  grayish  brown  as 
the  invaded  tissues  die.  In  severe  cases  they  coalesce  involving  considerable  por- 
tions of  the  leaf-blades.  In  the  worst  cases  practically  all  of  the  leaves  of  affected 
plants  are  dried  up  at  about  flowering  time.  In  moist  weather  the  fungus  sporulates 
abundantly  on  the  older  lesions.  On  orchard  grass,  the  lesions  are  somewhat  more 
distinctive  and  sporulation  takes  place  more  abundantly.  The  conidiophores  come 
out  through  the  stomata  and  form  dark-colored  tufts  arranged  rather  regularly 
in  rows. 

Other  grasses  observed  by  the  writers  as  hosts  for  the  fungus  are  Agrostis  alba, 
Bromus  margimitus,  Bromus  sitchensis,  Hordeum  jubatum,  Hordeum  nodosum,  Ely" 
mus  glaucus  and  Elymiui  robustus. 

Observations  at  Madison  have  shown  that  the  fungus  over-winters  readily  in 
tufts  of  orchard  grass  and  timothy  and  resumes  activity  early  in  the  spring. 

Bacteria  of  barley  blight  seed-borne,  L.  R.  Jones,  A.  G.  Johnson,  and  C.  S.  Reddt 
*  In  further  studies  on  the  bacterial  blight  of  barley,  upon  which  reports  have 
been  previously  made,  the  mode  of  overwintering  of  the  causal  organism  and  of  its 
dissemination  over  long  distances  have  received  especial  attention.  Field  evidence 
early  indicated  that  in  certain  cases  the  disease  doubtless  was  introduced  with 
seed  from  various  western  sources.  In  following  up  this  matter,  seed  was  collected 
in  1914  from  a  field  of  barley  in  Montana  severely  affected  by  the  blight.  Lesions 
were  evident  on  the  glumes  of  these  plants  before  maturity  and  showed,  although 
less  clearly,  upon  the  ripe  grain.  Some  of  this  seed  was  planted  in  our  trial  grounds 
in  Wisconsin  in  1915,  and  the  blight  developed  abundantly  upon  the  leaves  of  the 
young  plants. 

Isolation  cultures  were  made  in  July,  1916,  from  the  glumes  of  barley  kernels 
from  this  same  1914  Montana  collection.  The  characteristic  barley  blight  organism 
was  obtained  and  its  pathogenicity  proved  by  inoculation  experiments.  It  is  thus 
apparent  that  the  organism  may  be  carried  with  the  seed  grain  and  remains  viable 
after  at  least  two  years  of  dormancy.  Preliminary  trials  indicate  that  the  organism 
may  be  destroyed  by  seed  disinfection. 


70  Phttopathologt  [Vol.  7 

The  Ptteudopeziza  leaf  spot  diseases  of  alfalfa  and  red  clover,    Fred  Reucl  Jonks 
The  PseudopeEiEa  leaf  ftpots  of  alfalfa  and  red  clover  have  been  studied  for  the 
past  two  yearn  for  the  purpose  of  determining  the  following  points. 

1.  Are  the  causal  organisms  the  same  or  distinct  species? 

2.  Is  any  other  spore-form  than  the  ascospore  included  in  the  life  history  of  these 
fungi? 

3.  What  is  the  relation  of  these  fungi  to  the  tissues  of  their  hosts? 

4.  How  do  these  fungi  oven»inter? 

5.  Can  the  occurrence  of  the  alfalfa  leaf  spot  on  alfalfa  sown  in  a  new  region  for 
the  first  time  he  prevented  by  seed  treatment? 

Progn^s  hat*  been  made  as  follows: 

1.  Both  fungi  have  been  obtained  in  pure  cylturc.  Slight  morphological  and 
distint't  phyniologiral  differences  have  been  found. 

2.  Only  ftf^cosporcs  have  been  found  produced  in  nature.  Conidia-like  structures 
occur  in  cultures. 

3.  (icnninnting  aMcospores  penetrate  the  epidermal  cells  directly  and  the  mycelium 
devt'lopM  within  the  ho»t  ccIIh  and  penetrates  the  cell  wuIIh. 

4.  The  fungtiH  <)ver>»inters  on  dead  leaves  which  escape  <lecay,  and  ascospores 
developiMl  either  in  old  or  new  apothecia  are  a  source  of  spring  infection. 

5.  .Mfalfa  serd  very  th(»roughly  (iisinfcrt«*<l  has  been  sown  at  distances  up  to  15 
miles  from  other  alfalfa.     Leaf  spot  has  occurred  on  all  these  plots. 

The  development  of  the  aeciid  Mtagc  of  \igredo  on  red  rlorer.     I.  K.  Meliits  and  Wil- 
liam   DiKHL 

Th«*  orrurrence  of  the  ure<liiio-  and  teli<»spore  stages  of  Sigredo  fallens  (Desm.) 
Arthur  \l'rom\fetn  fallem*  (I)esni.)  Kern)  on  red  clover  {Trifolium  pratense)  is  com- 
mon, but  the  aecial  stagt*  of  this  nist  is  apparently  not  well  known.  The  ure<iino- 
spore  stage  di'velopi**!  abundantly  on  re<l  rlover  growing  in  the  greenhouse  l>egin- 
niiig  Hb<»ut  Januarx  10.  VJU),  when  ihe  clovei  plantswere  alniut  six  inches  tall.  These 
grew  in  pots  forming  a  border  nearest  tin*  glass  on  a  bench  in  a  house  where  the 
temprrnturr  rang(*il  from  10"  at  night  to  '2(f(\  in  the  day  time.  On  .March  26, 
Il»l*>.  a«MMa  Urn*  nlisrrv<*<l  <»n  the  leaves  of  the  red  cIovit  plants.  During  the  next 
two  uf«*ks  the  aerial  stag**  breaine  abundant.  It  rontinued  to  develop  for  about 
a  month  whrti  the  tmnpcrature  raised  in  th<*  h(»use  due  to  the  increaseti  sunshintv 
Whit*'  rIovMT  \Trift'hum  refnnf*),  alsike  ( 7\  hifhridumi,  and  crimhon  cl<»ver  (7*.  i«- 
earnatumi.  growing  ui  close  proximity  were  c<intinually  free  fnmi  infection. 

H<-p«*at(il  att<'mpts  were  niadt*  to  transfer  the  rust  to  the  above  hosts  by  using 
the  acrio?.pon'f«  but  no  infections  were  obtained  except  on  the  re<i  clover.  It  would 
appear  that  .Vi*;r«#/n/*i//«  n/*  is  autm*cious  and  not  lieter(K'cious  as  h<*retofore  reportwl. 

.4  rnoluutrittnu  timtaite  of  the  Irish  jnttnto  and  itf<  rnntrtd.      II.  .\.  Kl)HO.\  and  Oswald 

SlIHIllNKU 

liegitiiiing  eariv  in  the  past  July,  potato  plants  in  numerous  eastern  fields  from 
Mauie  to  N'irginia  developed  a  downward  curling  of  the  leaf  margins  accompanicNi 
by  a  bronzing  and  later  a  brriwning  but  not  a  yellowing  of  the  foliage.  Death  of 
the  leaves  and  sudden  collapse  of  the  stems  at  the  ground  level  follow<Hl.  Fungi 
of  parasitic  habits  a|>peared  at  and  above  the  |M>int  of  collapse.  Dr.  W.  A.  Orton 
c»b»erved  the  disease  in  New  Jersey  an<l  note«l  its  absence  fn»m  areas  treated  with 
fM»tn«>h  or  stable  manure.  Similar  obsi'rvations  were  made  elsewhere.  partieuUtrly 
in  Mame.  where  Dr.  Joseph  l{os4*nbaum  and  B.  K.  Hrown  ami  L.  A.  Hurst  have 


1917]  New  York  Meeting  71 

undertaken  a  study  of  the  disease  in  cooperation  with  the  Maine  Agricultural  Ex- 
periment Station.  These  investigations  are  incomplete  but  present  indications 
are  that  the  fungi  isolated  are  weakling  parasites  operating  as  contributing  factors 
and  that  the  primary  cause  is  malnutrition,  resulting  from  insufficient  potash  or 
perhaps  an  excess  of  nitrates  in  the  presence  of  a  minimimi  potash  supply.  In  Maine 
the  disease  appears  to  be  correlated  with  certain  soil  types  and  is  most  marked  on 
Irish  cobbler,  Bliss  and  Eureka,  though  not  entirely  restricted  to  these  early  varie- 
ties.   Stable  manure  is  an  excellent  corrective. 

Notes  on  curly  dwarf  symptoms  on  Irish  potatoes.    W.  L.  Durrell 

Plants  showing  curly  dwarf  symptoms  were  very  prevalent  in  Iowa  this  past 
season  on  the  varieties  Irish  cobbler.  Rural  new  yorker  and  Early  ohio.  In  some 
cases  these  symptoms  were  on  plants  grown  from  the  progeny  of  plants  having  shown 
curly  dwarf  symptoms  the  preceding  year;  in  others  they  were  induced  by  climatic 
conditions.  The  disease  made  its  appearance  on  the  early  planting  about  June  10 
and  continued  to  develop  throughout  the  season.  In  August,  plants  that  had  been 
normal  up  imtil  that  time,  showed  typical  signs  of  curly  dwarf  on  the  foliage  pro- 
duced during  this  period.  The  upper  third  of  the  plant  had  shortened  internodes, 
crinkled  and  curled  leaves,  giving  this  portion  of  the  plant  a  bushy  appearance  so 
characteristic  of  curly  dwarf.  These  symptoms  were  induced  in  the  field  by  the 
hot  dry  weather  during  August  and  similar  ones  were  later  artificially  developed 
in  the  laboratory.  The  plants  manifesting  these  induced  symptoms  of  curly  dwarf 
put  forth  normal  foliage  again  in  September  with  the  advent  of  cooler  weather. 

Histological  studies  show  that  the  crinkling  of  the  leaves  is  due  to  necrosis  of 
certain  epidermal  and  cortical  cells  of  the  veins,  followed  by  the  growth  of  the  par- 
enchyma cells  which  induces  a  buckling  of  the  leaf  surface.  In  addition  the  leaves 
showing  curly  dwarf  symptoms  were  characterized  by  a  most  marked  decrease  from 
the  normal  in  the  size  of  the  parenchyma  cells.  Furthermore  transpiration  tests 
using  the  cobalt  chloride  paper  and  potometer  methods  indicate  that  curly  dwarf 
plants  transpire  more  rapidly  than  normal  ones. 

Notes  on  mosaic  symptoms  of  irish  potatoes.    I.  E.  Melhus 

The  so-called  mosaic  disease  of  potatoes  is  characterized  by  yellow  mottling  and 
crinkling  of  the  foliage.  Its  effect  on  the  potato  plant,  transmissibility,  and  rela- 
tion to  curly  dwarf  is  very  imperfectly  understood.  The  varieties  of  Bliss  triumph 
and  Green  mountain,  which  showed  mosaic  symptoms  in  1914  and  1915  in  northern 
Maine,  were  planted  in  1916  at  Ames,  Iowa.  The  characteristic  yellow  mottling 
typical  of  this  disease  did  not  develop  at  any  time  during  the  growing  season.  Curly 
dwarf  symptoms,  however,  were  prevailingly  present. 

(a)  Plants  seemingly  badly  affected  in  1915  produced  0.237  pounds  per  hill. 

(b)  Plants  seemingly  moderately  affected  in  1915  produced  0.29  pounds  per  hill. 

(c)  Plants  seemingly  slightly  affected  in  1915  produced  0.32  pounds  per  hill. 
Healthy  plants  used  as  checks  produced  0.46  pounds  per  hill. 

None  of  the  plants  in  lots  a  or  6  grew  as  large  as  those  in  lot  c,  but  some  of  the 
c-plants  were  like  those  of  a.  Although  the  typical  mottling  characteristic  of  mo- 
saic in  certain  northern  potato  growing  districts  may  not  develop,  the  progeny 
of  plants  showing  these  symptoms  are  undesirable  for  seed  purposes. 

Frost  necrosis  of  potato  tubers.    L.  R.  Jones  and  Ernest  Bailet 

A  peculiar  type  of  non-inheritable  "net  necrosis"  of  potato  tubers  has  been  under 
observation  for  several  years  under  conditions  suggesting  frost  injury.     Carefully 


72  Phttopatholoqt  [Vol.  7 

repeated  ohilliog  experiments  confirm  this  hypothesis.  Tubers  ''frosen  toUd"  are 
totally  killed  and  collapse  when  thawed.  If,  however,  the  chilling  stops  with  in- 
cipient ice-crystallisation,  killing  may  be  confined  to  such  interior  tissues  as  are 
most  sensitiye.  Such  chilled  tubers  appear  normal  externally  but  when  cut  show 
the  interior  vascular  regions  to  be  most  sensitive  and  hence  the  first  to  succumb 
and  discolor.  Therefore,  moderate  exposure  to  freesing  temperature  may  pro- 
duce either  ''ring"  or  "net"  necrosis,  the  blackened  vascular  portions  permeating 
the  starchy  fundamental  tissues.  Individual  variations  in  sensitiveness  occur  be- 
tween tubers,  but  in  general  the  best  t3rpe8  of  ''net  necrosis"  have  been  secured 
by  about  two  hours  exposure  to  +5*C.,  with  similar  results  by  exposures  ranging 
from  —  l^C.  for  8.5  hours  to  —  9*^0.  for  one  hour.  Slightly  more  severe  treatments, 
or  unequal  exposures  may  give  frosen  spots  with  corresponding  dark  blotches  in- 
volving the  general  parenchyma.  The  stem  end  of  the  tuber  is  always  more  sensi- 
tive than  the  other. 

Will  Spongoapora  subterranea  prove  serious  in  Virginia?    J.  A.  McCuntock 

Potatoes  affected  with  powdery  scab  planted  in  Virginia  in  the  spring  of  1916 
produced  a  crop  free  from  this  disease.  In  the  spring  of  1916  affected  tubers  from 
Maine  were  planted  at  Norfolk,  Virginia,  and  at  Tasley,  on  the  Eastern  Shore  of 
Virginia.  The  writer  examined  the  crop  at  each  place  but  found  no  signs  of  Spon- 
gospora  infection  on  any  of  the  harvested  tubers.  Some  of  the  infected  seed  from 
Maine  was  held  over  summer  in  cold  storage  and  planted  at  Norfolk  about  the 
time  the  fall  crop  of  Irish  potatoes  was  planted  in  Virginia.  On  November  23,  1910, 
the  tubers  were  harvested  and  examined  but  no  Spongospora  infection  was  observed. 
These  results  corroborate  those  of  1915  and  lead  one  to  conclude  that  powdery 
scab  will  not  be  prevalent  either  on  the  spring  or  fall  planted  potatoes  even  though 
the  seed  tubers  are  infected  with  Spongospora  subterranea. 

Seed  potato  certification  in  Nova  Scotia.     Paul  A.  Murpht 

Many  fields  of  Garnet  chili  potatoes  for  the  Bermuda  seed  trade  were  infected 
to  the  extent  of  fifty  per  cent  with  leaf  roll,  and  whole  districts  to  not  less  than  ten 
per  cent,  making  a  difficult  situation  when  we  took  charge.  Hill  selection  in  dis- 
tricts proved  useless  in  several  cases  tried.  The  scheme  adopted  had  to  be  a  com- 
pn»hensive  and  unusual  one,  an  outline  of  which  follows. 

It  is  neccHsary  for  growers  to  start  with  stock  of  good  previous  record.  This 
provision,  which  is  absolutely  insisted  on,  is  becoming  more  stringent,  and  in  two 
years  the  growers  will  use  exclusively  stock  which  is  now  selected  and  is  being  given 
a  three  years'  trial.  Thereafter  it  will  still  be  continuously  selected,  one  man  be- 
ing ap|H)intecl  in  each  district  to  grow  it  for  his  ncigbors. 

The  munriier  inspection  iM  made  jointly  by  officerH  of  the  Departments  of  Agri- 
culture of  (*anada  and  Bermuda,  while  the  autumn  inHpection  is  made  by  the  Cana- 
dian aiithoritii*?*.  The  grower'n  name  appearH  on  each  barrel,  whereby  many  stocks 
are  trurcd  to  the  Bennuda  pint  at  ions.  Am  a  further  nafeguard  a  sample  of  every 
gruwcr'M  potatoes  are  ^eiit  to  Bennuda,  where  they  are  all  plante<l  together. 

The  fcornfmw  importance  of  mosaic  of  potato.     Vm'L  \.  Mukphy 

The  b<*ginning  of  a  serii»«  of  experiments  to  inve«tigate  the  economic  importance 
of  iUin  dineaite  han  given  striking  resultn.  In  one  ex|K*rinient  of  eleven  similar  plots 
Hide  by  Hide,  plaiit^Ml  partly  with  ht^althy,  and  partly  with  mosaic-diseased  Green 
mountains  of  the  name  strain,  the  dim^aiuti  plants  gave  a  yield  which  was  on  the 


1917]  New  York  MEBTma  73 

average  only  57.8  per  cent  that  of  the  normal  plants,  the  limits  being  52.0  per  cent 
and  63.6  per  cent.  Furthermore  the  crop  of  the  mosaic-diseased  plants  was  mar- 
ketable only  to  the  extent  of  82.7  per  cent  (limits,  74.1  and  87.3),  while  91.6  per  cent 
of  the  crop  of  the  healthy  plants  was  marketable  (limits,  81.9  and  94.1).  This  means 
that  in  an  average  crop  of  300  bushels  there  is  a  loss  of  one  and  one-third  bushels 
of  marketable  potatoes  for  every  1  per  cent  of  mosaic  present.  This  coupled  with 
the  fact  that  the  trouble  is  constant  every  year  and  that  it  generally  affects,  where 
present,  not  far  from  twenty  per  cent  of  the  crop  means  a  steady  loss  of  from  twenty 
to  thirty  bushels  of  potatoes  per  acre  per  year.  The  eating  qualities  of  the  pota- 
toes are  not  impaired. 

A  new  strain  of  Puccinia  graminis,    E.  C.  Stakman  and  F.  J.  Piemeisel 

A  rust  which  behaves  differently  from  any  of  the  common  biologic  forms  of  Puc' 
cinia  graminta  has  recently  been  found  on  club  wheat  and  a  number  of  wild  grasses. 
It  resembles  P.  graminia  tritici  morphologically  and  parasitically  more  that  it  does 
any  other  biologits  form.  However,  the  common  Trittcum  vtUgare  wheats  which 
have  been  inoculated  are  highly  resistant  to  it.  Both  P.  graminis  tritici  and  the 
new  strain  have  a  niunber  of  hosts  in  common,  viz:  Triticum  compactumf  Barley, 
Agropyron  smithiif  Elymus  canadensis,  Elymus  macoum't,  and  Hordeum  jubatum. 
The  new  strain  has  also  been  found  in  nature  on  Elymus  glattcus  and  E,  condenscdus 
and  has  infected  a  number  of  grasses  in  the  greenhouse.  Extensive  cross-inocula- 
tion experiments  are  now  under  way. 

The  rust  was  found  only  west  of  the  Rocky  Mountains  in  Idaho  and  Washing- 
ton where  it  seemed  to  take  the  place  of  ordinary  P.  graminis  tritici,  none  6i  which 
was  foimd  in  the  region  mentioned. 

Puccinia  graminis  on  wheat  kernels  and  its  relation  to  subsequent  infection.    Chab. 

W.  HUNGERPORD 

Various  workers  have  noted  the  occurrence  of  rust  pustules  on  seeds  of  different 
grains  and  some  have  held  that  the  fungus  might  infect  the  plant  by  this  means. 
Experiments  have  been  carried  on  at  Madison,  Wisconsin  the  last  year  to  deter- 
mine if  possible  whether  Puccinia  graminis  is  able  to  infect  wheat  through  the  seed. 
Three  lines  of  attack  have  been  followed,  (a)  Rusted  seed  after  being  germinated 
at  different  temperatures  has  been  fixed  and  examined  by  histological  methods  and 
in  no  case  was  the  fungus  found  to  penetrate  the  embryonic  tissues,  (b)  Treated 
and  untreated  samples  of  rusted  seed,  as  well  as  clean  seed,  were  planted  in  the 
field  and  the  first  appearance  of  stem  rust  upon  the  plants  in  the  different  plots 
was  noted  at  practically  the  same  time,  (c)  Two  lots  of  rust-infected  seed  have 
been  grown  to  maturity  in  an  isolated  room  in  the  greenhouse.  No  rust  has  ap- 
peared on  any  of  these  plants.  Although  the  work  has  not  been  fully  completed, 
the  results  so  far  tend  to  show  that  seed  wheat  infected  with  Puccinia  graminis 
does  not  cause  infection  of  the  wheat  plant. 

Similar  experiments  are  being  started  at  Corvallis,  Oregon,  with  wheat  infected 
wi  th  Ptu:cinia  glumarum. 

Ecological  observations  on  Ustilago  Zeae.  Alden  A.  Potter  and  Leo  E.  Melchers 
Pammel  and  Stewart  in  1893  observed  that  the  nodal  buds  of  maize  were  particu- 
larly subject  to  smut  and  that  "where  one  smut  boil  made  its  appearance  on  the 
lower  nodes,  others  appeared  further  up.''  It  thus  becomes  desirable  to  explain 
how  the  infection,  shown  by  Brefeld  to  be  strictly  local  in  its  development,  can 
spread  on  the  plant.    The  basis  of  study  has  been  Brefeld' s  idea  of  distribution  by 


74  Phytopathology  [Vol.  7 

air-l>orne  conidia.  The  organism  han  boon  iflolated  in  pure,  conidial  culture,  both 
from  the  air  and  from  the  young  plants  some  little  time  before  the  disease  appeared. 
The  com  plant  is  thus  seen  to  be  well  adapted  as  a  spore  trap.  The  conidia  caught 
probably  do  not  infect  directly.  The  result  is  rather  the  development  of  a  virulent 
culture  in  the  leaf  axil.  A  plant  may  thus  become  a  center  of  aerial  distribution; 
or,  when  rain  recurs,  the  conidia  may  be  washed  down  or  splashed  out  upon  other 
leaves.  Thus  it  may  sometimes  happen  that  all  the  culms  of  a  plant,  or  hill,  will 
show  many  no<lal  infections  when  an  equal  number  of  stalks  immediately  adjacent 
will  not  be  infecte<l  at  all. 

The  shart-cyrUd  Vromycen  of  Xorth  America.     G.   li.  Hishy 

Only  eleven  species  of  short -<*yrle<l  rnmiyces  huvc  boon  found  in  Xorth  America. 
Those  nists  are  parasitic  upon  six  families  of  Monocotylodons  and  Dicotyledons. 
Various  relationships  are  evident  botwoon  those  rusts  and  other  long-cycled  and 
short-cycled  species  of  ruMts.  Seven  sperios  arc  commonly  micro-forms;  for  four 
of  th(»so,  pyrnia  are  known.  Seven  sperios  have  strictly  local  mycelium.  These 
nists  occur  mainly  in  WcHtcrn  and  Southern  North  .Vniorira.  The  specimens  have 
been  studied  at  the  Arthur  HerbarUim. 

Holed  and  mycorhiza  uf)on  forest  trees  and  an  unusual  mycorhiza  ujwn  trhite  oak. 

L.  H.  Pe.vxington 

One  instance  of  a  Boletus,  li.  nperiosus  Frost,  connect o<l  with  mycorhiia  of  oak 
was  reported  in  VJilH.  Since  that  time  five  other  species,  li.  froHtii  Kussell,  B.  in- 
deMiitu*  I*k.  li.  chroma ften  Frost,  li.  purpureus  Vr.  and  H.  gracilis  Pk.  have  been  found 
conn«»ct<»<l  with  mycorhiza  of  forest  trees,  usually  oaks.  Two  of  these  species, 
a.  froftiii  and  H.  indecisun,  have  been  found  to  produce  sclerotia  similar  to  those 
report e<l   f<»r  li.  sfxciimuM. 

A  peculiar  form  of  mycorhiza  was  found  upon  white-oak  roots  in  which  the  hy- 
p<Ttrophie<l  branches  are  closely  aggrogateii  and  surrounded  by  a  peridium-like 
layer  of  fungal  tissue.  This  gives  them  the  appearance  of  white  root  tubercles, 
four  to  twolve  millimeters  in  <liameter.  These  tuborcle-liko  growths  are  not  unlike 
thos<»  uiH)n  bee<'h  roolH  d«»scribe<i  in  1890  by  Von  Schronk.  They  are  also  definit<*ly 
connoctecl  with  small  sclerotia  from  which  there  in  a  growth  of  mycelium  in  early 
summer  to  prcHluoe  now  mycorhiza  U(Mm  the  roots.  .\t tempts  to  inoculate  the 
nK)tH  of  oth(*r  treses  with  this  fungus  have  thus  far  failo<l. 

A   nrw  paranitic  nlime  mold  nuitahle  for  class  tatrk.     John  A.  Klliott 

The  Hwoot  [lotato  "|m>x"  organi-nm,  Cystosfntra  haiata  Klliott,  as  it  occurs  on  sweet 
|x>tftt<M'?«,  offors  itself  an  an  oxrollont  «*xainplo  of  the  Plu.*<mo<liophoral(*s  for  use  in 
tho  Inbonitory.  Infort<'<l  i>IniitM  growing  botwoon  shoots  of  moist  blotting  paper 
afTnrd  »ii  abundatiro  nf  pnriu«itizo4l  rootlets  and  growing  i>oints  of  stems  for  free- 
hand !*«'<>! ioiiiiig  or  for  oiiibo<idiiig  in  paraffin.  Such  matorial  iH  easily  sectioned 
and  rontaiii^  groat  numborM  of  tin*  para>ito  in  all  stag<'H  of  its  life  cycle.  The  rapid- 
ity uitli  \iliirh  tho  organism  goos  through  its  complete  life  history  makes  a  study 
of  living  nmtoriul  of  ^pecial  value. 

Straiuf  nf  Hhiztuiimia.     J.    RosKMiAt'M  and  M.  Siiapavalov 

During  tho  mimmor  of  llll(>  a  strain  of  Hhizootonia  was  isolated  from  potato  steins 
which  showinl  a  girdling  and  hollowing  at  or  near  the  surface  of  the  ground.    This 


1917]  New  York  Meeting  75 

strain,  designated  R  5,  differs  in  the  following  particulars  from  other  strains  isolated 
from  stems  and  tubers  of  potatoes  grown  in  Maine  and  Florida: 

(1)  Inoculations  with  R  5  produced  definite  lesions  in  injured  potato  stems  grow- 
ing in  the  field  and  greenhouse  and  injured  tubers,  while  in  the  case  of  inoculations 
with  other  strains  the  lesions,  if  produced  at  all,  were  smaller  and  the  results  not  so 
conclusive.    The  injured  checks  remained  healthy. 

(2)  Macroscopically  R  5  can  be  distinguished  by  the  darker  coloration  of  the 
medium,  especially  when  grown  on  potato  agar,  and  by  the  light  grayish  sclerotia 
as  compared  with  the  dark-brown  sclerotia  of  the  others  when  grown  on  corn-meal 
agar. 

(3)  Microscopically  R  5  differs  from  the  other  strains  in  its  finer  mycelium,  w>>ich 
measures  5  to  9  m  in  diameter  while  the  others  measure  10  to  14  /x. 

Is  it  not  possible  that  different  strains  of  Rhizoctonia  may  offer  an  explanation 
for  the  conflicting  reports  regarding  artificial  infection? 

The  aerial  stage  of  the  red  clover  rust.    W.  H.  Davis  and  A.  G.  Johnson 

The  well  known  red  clover  rust,  Uromyces  fallens  (Desm.)  Kern,  has  long  been 
suspected  of  having  an  aecial  stage.  Our  observations  and  experiments  have  thrown 
definite  light  on  the  question. 

Aecia  on  red  clover  were  first  obtained  experimentally  in  the  greenhouse  in  Decem- 
ber 1915  and  similarly  again  in  January  and  February,  1916.  Later  in  the  spring 
a  number  of  cases  of  aecia  were  observed  on  the  same  host  out  of  doors  near  Madison. 
Following  various  sowings  of  aeciospores  from  such  sources  on  rust-free  red  clover 
plants  under  glass,  uredinospores  developed  uniformly.  These  were  identical  with 
those  conmionly  observed  on  that  host.  Sowings  of  viable  teliospores  resulted  in 
the  development  of  aecia,  identical  with  those  observed  in  greenhouse  and  field. 
It  is  thus  evident  that  this  rust  is  a  long-cycled  autoecious  species,  i.e.,  with 
pycnia,  aecia,  uredinia  and  telia  on  the  same  host. 

Observations  on  pear  blight  in  Illinois.    F.  L.  Stevens,  W.  A.  Ruth,  G.  L.  Peltier, 

and  J.  R.  Malloch 

Experiments  made  by  applying  Bacillus  amylovorous  in  suspension  in  water  to 
pear  buds  in  1915  did  not  indicate  in  1916  that  the  bacilli  hibernated  in  the  buds. 

Subcuticular  infections  of  spurs  from  hold-over  trunk  cankers  occurred  in  1916, 
with  a  maximum  number  of  twelve  such  infections  from  one  canker.  The  organ- 
ism appeared  to  be  dead  in  all  twig  cankers.  A  few  living  cankers  provided  exudate 
for  serious  well-distributed  blossom  infection,  which  in  turn  provided  exudate  for 
further  infections,  these  continuing  until  early  in  June. 

Leaves  appeared  to  be  at  no  time  naturally  infected  from  the  exterior  and  on 
June  1  blades  and  pedicles  could  not  be  inoculated  though  the  fruit  and  pedicles 
were  still  susceptible.  Bordeaux  mixture  controlled  the  floral  infection  without 
reducing  the  set  of  fruit. 

Second  progress  report  on  investigations  of  leaf  spot  of  cherries  and  plums  in  Wisconsin. 

G.  W.  Keitt 

Comparative  studies  of  Coccomyces  hiemalis  Higgins  and  related  organisms  in 
connection  with  leaf  spot  diseases  of  cherries  and  plums  have  been  continued,  and 
spraying  and  sanitation  experiments  in  the  control  of  cherry  leaf  spot  have  been 
begun.     Only  the  control  work  is  reported  here. 

Spraying  (Montmorency  and  Early  Richmond).  In  early  summer,  the  disease 
occurred  in  unusual  severity,  but,  after  the  advent  of  hot  dry  weather  in  late  July, 


76  Phttopatholoot  [Vou  7 

it  made  relatively  little  progress.  It  was  satisfactorily  controlled  by  Bordeaux 
mixture,  4-4-50,  3-3-50,  and  2-2-50,  and  lime-sulphur  (commercial  ooncentrmte, 
33*B.),  1-10,  applied  (1)  when  the  petals  fell,  (2)  l(m7  days  later,  and  (3)  just  after 
the  fruit  was  harvested.  "Atomic  sulphur,"  5-50;  barium-sulphur,  3-50;  and  aelf- 
boiled  lime-sulphur,  8-8-50,  in  parallel  applications,  did  not  control  the  disease 
satisfactorily.  An  additional  application  just  before  the  blossoms  opened  did  not 
increase  the  efficiency  of  leaf  spot  control. 

Sanitaiian.  Life  history  studies,  sanitation  experiments,  and  extensive  obeerva- 
tions  indicate  that,  under  Wisconsin  conditions,  the  spray  schedule  may  be  strongly 
reinforced  by  turning  under  the  fallen  leaves  as  completely  as  feasible  by  clean  cul- 
tivation before  the  blossoms  open  (In  1016,  the  first  ascospore  discharge  was  observed 
as  cherry  blossoms  began  to  open). 

Jonathan  spot,    Charles  Brooks  and  J.  S.  Collet 

The  development  of  Jonathan  spot  increases  with  an  increase  in  temperature  up 
to  20*C.,  but  is  entirely  inhibited  at  dO'^C.  The  disease  can  be  readily  produced 
in  saturated  air  in  closed  moist  chambers  but  seldom  develops  in  a  stirred  air  of 
70  per  cent  or  95  per  cent  relative  humidity. 

Temperature  relation*  of  apple  rot  fungi.    Charles  Brooks  and  J.  S.  Collet 

Most  apple-rot  fungi  will  grow  at  a  lower  temperature  on  com  meal  agar  than 
on  fruit  and  at  a  lowor  temperature  on  ripe  fruit  than  on  green  fruit.  With  several 
if  not  all  of  the  storage-rot  fungi  the  initial  stages  of  rotting  are  more  inhibited 
by  low  temperatures  than  is  the  germination  of  the  spores.  Rots  may  finally  make 
a  fairly  rapid  development  at  temperatures  at  which  the  fungus  is  at  first  barely 
able  to  make  a  start.  Even  at  favorable  temperatures  most  of  the  fungi  pass  through 
a  period  of  incubation  on  apples  that  is  not  evident  on  culture  media. 

Control  of  apple  §cab  by  bleaching  poicder.    W.  S.  Brock  and  W.  A.  Ruth 
Bleaching  powder  when  applied  to  apple  trees  in  1016  reduced  apple  scab  from  50 

per  cent  to  11.2  per  cent.     No  injury  resulted  to  fruit  or  foliage.    The  leaves  on 

trees  sprayed  with  this  material  were  practically  free  from  scab.    Leaves  on  un- 

■prayed  trees  showed  serious  seal)  infection. 
In  1010  the  material  was  applied  at  high  concentrations  alone,  and  with  lime, 

causing  little  foliage  injury,  but  no  scab  developed.     Higher  concentrations  alone 

and  in  combination  with  other  materials  will  be  tried. 

Studie*  on  peach  yello%c»  and  little  peach.    M.  A.  Blake,  Mel.  T.  Cook  and  C.  A. 

ScHm-AKiR 

S>'mptoms  ver>'  iiimilar  to  peach  yellown  and  little  peach  may  be  due  to  other 
causes.  Tents  with  healthy  and  diHcaiMHl  trees  showetl  (1)  pulp  from  healthy  leaves 
retains  original  color  longer  than  pulp  from  ditieased  leaves;  (2)  juice  from  healthy 
leaves  in  more  mucilaginous  than  that  from  diseased  leaves;  (3)  juice  from  fast- 
growing  trecM  more  niurilaginoun  than  juice  from  the  leaves  of  slow-growing  trees; 
(4)  leaves  taken  from  healthv  trees  after  sunset  showe<l  a  minimum  amount  of 
starch,  leaves  from  little  peach  trees  a  larger  amount,  and  leaves  from  yellows  trees 
and  from  girdle<l  trees  the  greatest  amount;  (5)  leaves  from  an  apparently  healthy 
branch  a<ljacent  to  a  diseased  branch  on  same  tree  showed  a  higher  starch  content 
than  leaves  from  a  healthy  tree;  (7)  leaven  from  fast-growing  trees  lose  starch  more 
rapidly  than   leaves  from  slow-growing  trees;   (8)  juice  extracted  from  healthy 


1917]  New  York  Meeting  77 

leaves  showed  less  oxidase  than  juice  from  diseased  leaves;  (9)  juice  from  healthy 
kernels  showed  less  catalase  and  acid  than  juice  from  diseased  kernels;  (10)  the  tan- 
nin content  of  healthy  fruit  is  less  than  that  of  diseased  or  forced  fruit. 

Pits  from  diseased  trees  failed  to  germinate.  Budding  experiments  with  dis- 
eased buds  indicate  that  the  appearance  of  the  disease  in  the  young  trees  varies 
with  source  of  bud  wood. 

A  Xylaria  root-rot  of  the  apple.    F.  D.  Fromme  and  H.  E.  Thomas 

A  destructive  root-rot  of  apple  trees  is  prevalent  in  the  chief  orchard  sections  of 
Virginia.  The  infectiousness  of  this  condition  is  shown  in  the  death  of  adjoining 
trees  in  groups  irrespective  of  soil  conditions  or  topography,  and  in  the  death  of 
replants  set  in  holes  from  which  diseased  trees  were  removed.  Isolations  from 
affected  roots  from  a  number  of  orchards  have  yielded  cultures  of  a  fungus  which 
is  apparently  the  conidial  stage  of  a  species  of  Xylaria.  Perithecial  stromata  of 
Xylaria  polymorpha  have  been  found  on  roots  of  apple  trees  showing  typical  attack. 
Tjrpical  root-rot  lesions  have  been  produced  with  pure  cultures  of  the  Xylaria  in- 
troduced into  bark  woimds  of  living  apple  roots  in  damp  chambers  and  in  the  field. 
The  introduced  fungus  has  been  recovered  in  pure  culture  from  these  lesions.  Two 
or  more  species  of  Xylaria  may  be  involved;  their  interrelations  are  subject  fgr  fur- 
ther study.  Apparently  all  varieties  of  apples  are  susceptible  and  probably  equally 
so.  Observations  indicate  that  the  organism  may  be  spread  in  cultivation,  in  the 
removal  of  borers,  in  contact  between  root  systems  of  adjoining  trees  and  in  sur- 
face washing  of  infective  material. 

Pycnial  acars,  an  important  diagnostic  character  for  the  white  pine  blister  rust.    Regi- 
nald H.  COLLEY 

After  the  pycnospores  appear  in  their  characteristic  sweetish  drops  the  whole 
pycnium  is  cut  out  by  a  protective  layer  of  tissue  which  forms  at  a  depth  of* several 
cells  below  the  pycnial  layer.  Everything  above  the  protective  layer  drys  out  and 
dies.  The  result  of  this  drying  is  a  rusty  brown  patch  or  scar  which  indicates  by 
its  size  the  extent  of  the  pycnium.  The  scars  are  dark  brown  and  glossy  at  first. 
Later  they  become  rusty  brown  with  a  dry  dusty-granular  surface.  They  average 
about  four  millimeters  in  diameter.  Pycnial  scars  are  a  positive  diagnostic  field 
character  for  the  white  pine  blister  rust,  here  reported  for  the  first  time.  They 
are  especially  valuable  when  the  bark  is  but  little  swollen,  and  when  there  is  no 
indication  of  aecia  or  of  aecial  scars. 

Mycelium  of  the  white  pine  blister  rust.    Reginald  H.  Colley 

The  uninucleate  mycelium  of  Cronartium  ribicola  forces  its  way  between  the  bark 
cells  of  white  pine,  frequently  forming  strands.  As  the  cells  are  forced  apart  the. 
bark  s\^'ells.  Haustoria  penetrate  practically  every  non-woody  cell  in  the  infected 
tissue.  The  sieve  tubes  become  plugged.  Hyphae  follow  the  ray  cells  past  the 
cambium  and  into  the  wood  for  a  distance  of  at  least  three  annual  rings.  Thus  the 
fungus  derives  nourishment  from  both  the  ascending  and  descending  currents  of 
sap.  The  morphological  characters  of  the  mycelium  are  definite  and  constant  un- 
der all  conditions  observed.  Therefore  the  mycelium  has  positive  diagnostic  value 
for  the  blister  rust  before  there  is  any  exterior  indication  of  spore  formation. 

The  binucleate  mycelium  in  Ribes  leaves  is  limited  in  extent.  Haustoria  are  rare. 
Uredinia  and  telia  form  quickly  and  burst  through  the  epidermis  easily. 

The  binucleate  mycelium  is  very  abundant  in  cases  of  petiole  infection  and  the 
haustoria  are  larger  and  more  numerous  than  in  the  lamina.  Normal  telia  are 
usually  produced  but  sometimes  they  are  formed  internally. 


78  Phytopathology  (Vol.  7 

A  fpecien  of  Chrysomyxa  new  to  North  America,    H.  S.  Jackson 

The  KpnuB  Chrynomyxa  was  efltablished  in  1840  by  Unger  with  C.  abietis  (Wallr.) 
Vng.  aM  the  t>'pe  spccieD,  and  has  generally  been  interpreted  as  including  both  long 
and  short  cycle  forms.  Arthur  restricted  this  genus  to  include  only  the  micro- 
forms and  established  Melampsoropsis  (Schrot.)  Arth.  for  those  species  with  a  long 
life  cycle.  All  of  the  latter  forms  are  assumed  to  be  hcteroecious  and  have  their 
uredinia  and  telia  on  Pyrolaceae,  Ericaceae  and  Vacciniaceac.  The  aecial  stages 
so  far  as  determined,  have  proved  to  \tc  species  of  Peridcrmium  on  Picea.  In  America 
eight  species  have  been  reported,  all  of  which  are  long  cycle  forms  and  are  referred 
to  Melampsoropsis  by  Arthur.  Four  of  these  have  been  definitely  connected  through 
cultures  by  European  and  American  students  with  their  aecial  stages. 

A  short  cycle  form  referable  to  the  genus  Chr>'8omyxa  (as  restricted  by  Arthur) 
is  recogniEcd  in  America  for  the  first  time  and  causes  a  disease  of  the  leaves  of  Picta 
engelmannii . 

A  Gnomonia  on  eggplant.     C.  W.  Edgerton 

During  the  past  three  years,  a  species  of  Gnomonia  has  been  found  on  old  egg- 
plant stems  during  the  winter  season  at  Baton  Houge,  I^)uisiana.  This  fungus  has 
br<»n  repeate<lly  cultured  and  it  has  been  found  to  be  very  similar,  if  not  identical, 
from  a  morphological  standpoint,  with  the  fungus  causing  the  eggplant  blight, 
Phyltontirta  hnrtorum.  The  oval  Phyllostirta  spores  and  the  long  narrow  Phlyctaena 
spores  developc<l  in  culture.  Cultures  of  the  (inomonia  and  cultures  of  Phyllasticta 
hortarum  cannot  be  told  apart.  Inoculation  experiments,  however,  have  always 
been  negative.  While  it  may  be  that  the  Onomonia  has  no  connection  with  the 
Phyllosticta,  it  is  very  probable  that  the  two  are  closely  related  species. 


LITERATURE  ON  AMERICAN  PLANT  DISEASES* 

Compiled  bt  Eunice  R.  Oberly,  Librarian,  Bureau  op  Plant  Industry 

AND  Florence  P.  Smith,  Assistant 

October  to  November,  1916 

Avema-Sacca,   Rosario.    Molestias    cryptogamicas   da   canna   de    assucar.    Bol. 

Agr.  [Sao  Paulo]  17,  no.  8:  610-641,  illus.    Agosto,  1916. 
Brown,  F.  B.,  and  others.    Discussion  on  decay  in  timber.    Trans.  Canad.  Soc. 
Civ.  Engin.  29,  pt.  1 :  324r-365,  13  pi.    1915. 
Bibliography  of  timber  destroying  fungi,  p.  339-340. 
Clinton,  George  Perkins.    Report  of  the  botanist  for  1915.    Connecticut  Agr.  Expt. 
Sta.  1916,  pt.  6:  421-487,  pi.  17-26.    August,  1916. 

Notes  on  plant  diseases  of  Connecticut;  diseases  of  plants  caused  by  nema- 
todes; powdery  scab  of  potatoes;  potato  spraying  experiments,  3d  report. 
Literature,  p.  461-462,  469. 
Culpepper,  Charles  £.,  Foster,  Arthur  C,  and  Caldwell,  Joseph  S.    Some  effects 
of  the  blackrot  fungus,  Sphaeropsis  malorum,  upon  the  chemical  composition 
of  the  apple.    Jour.  Agr.  Research  7,  no.  1 :  17-40.    October  2,  1916. 
Literature  cited,  p.  39-40. 
Fromme,  Fred  Benton.    Facultative  heteroecism  (r)  of  Peridermium  harknessii 
and  Cronartium  quercus.    Phytopathology  6,  no.  5:  411-412.    October,  1916. 
Gorkum,  Nicolas  van.    A  molestia  do  olho  da  canna,  ponto-  de  vegetaySo,  corag&o 
e  peciolo  da  bandeira.    Bol.  Min.  Agr.  Indus,  e  Com.  [Brazil]  4,  no.  2:  105-112, 
3  col.  pi.    Abril/Junho,  1915. 
Gtissow,  Hans  Theodor.    The  grain  rust  in  the  prairie  provinces.    Agr.  Gaz.  Can- 
ada 3,  no.  10:  861-864.    October,  1916. 
Hawkins,  Lon  Adrian.    Growth  of  parasitic  fungi  on  concentrated  solutions.    Jour. 
Agr.  Research  7,  no.  5:  255-260.    October  30,  1916. 
Literature  cited,  p.  259-260. 
Hedgcock,  George  Grant,  and  Hunt,  N.  Rez.    Dothichiza  populea  in  the  United 
States.    Mycologia  8,  no.  6:  300-308,  pi.  194-195.     November,  1916. 
Literature  cited,  p.  308. 
Hesler,  Lexemuel  Ray.    Black  rot,  leaf  spot,  and  canker  of  pomaceous  fruits. 
New  York  Cornell  Agr.  Expt.  Sta.  Bui.  379:  49-148,  fig.  18-37,  pi.  7-14.    1916. 
Bibliography  [annotated],  p.  126-148. 
Home,  William  Titus.    The  importance  and   prevention  of  wood  decay  in  fruit 
trees.    Mo.  Bui.  State  Com.  Hort.  [California]  6,  no.  8: 278-282,  fig.  95-96.    Au- 
gust, 1916. 

1  This  list  aims  to  include  the  publications  of  North  and  South  America,  the  West  India  Islands,  and 
islanHs  controlled  by  the  United  States,  and  articles  by  American  writers  appearing  in  foreisn  Journals. 

All  authors  are  urged  to  co5perate  in  making  the  list  complete  by  sending  their  separates  and  by  mak- 
ing  oorrertions  and  additions,  and  especially  by  calling  attention  to  meritorious  articles  published  outside 
of  regular  journals.  Reprints  or  correspondence  should  be  addressed  to  Miss  E.  R.  Oberly,  librarian. 
Bureau  of  Plant  Industry,  U.  8.  Dept.  Agric,  Wsshington,  D.  C. 


80  Phytopathology  [Vol.  7 

Hotaon  John  WiUUm.    The  longevity  of  Bacillus  amylovorus  under  field  conditions. 

Phytopathology  6,  no.  5:  40(M08,  4  fig.    October,  1916. 
Johnson,  James.    Enfermedades  del  tabaco  y  manera  de  combatirlas.    Pt.  II-IV. 

Hacienda  IS,  no.  1:  26-28,  illus.,  Octubre;  no.  2:  6^-64,  illus.,  Noviembre;  no. 

3:  01-03,  illus.,  Diciombre.     1016. 
IH.  1  noted  in  previous  list. 
Host  plants  of  Thielavia  basicoia.    Jour.  Agr.  Research  7,  no.  6:  28^-^00. 

pi.  18-10.     November  6, 1016. 
Johnston,  John  Robert.    Phytopathological  work  in  the  tropics.     Phytopathology 

6,  no.  5:  381-386.    October,  1016. 

Jones,  Lewis  Ralph,  Johnson,  Aaron  Guy,  and  Reddy,  C.  S.  Bacterial  blights  of 
barley  and  certain  other  cereals.  Science  n.  s.  44,  no.  1134:  432-433.  Septem- 
ber 22,  1016. 

Long,  William  Henry.    The  aecial  stage  of  Coleosporium  ribicola.    Mycologia  8, 
no.  6:  300  311.     November.  1016. 
Peridcrmxum  rihiciAa. 

Matz,  J.  A  meth<Mi  to  induce  HiM>ruIation  in  cultures  of  Botryosphisria  beren- 
geriana.     Phytopathology  6,  no.  5:  387  380,   1  fig.     October.   1016. 

Meinecke,  Emillo  Pepe  Michael.  I^h  vanillidres  dc  Talnti  &,  de  M(M)rea.  Rap- 
port pr^>nt^*  tt  Mr  le  (louvcrneur  des  cstablissemcnts  fran^ais  de  TOc^anie. 
&  a  MM.  Icfl  niemhrcH  de  la  chambro  d'agriculture.     44  p.     Papeete,  1016. 

Maladies  it  leurti  rauM'M,  p.  13-28;  suppression  des  causes  des  maladies  de 
la  vanille,  p.  20  32. 

If  elchers,  Leo  Edward.    Diseases  affecting  Sudan  grass.     Kansas  Agr.  Expt.  8ta. 
Bui.  212:  16^-10,  pi.  4-^5.     1016. 
Kernel  smut;  treatment  of  s4M>d  to  kill  smut;  bliglit;  seedling  root  disease. 

Plant  disease's  afferting  alfalfa.     Upt.  Kannas  State  Bd.  Agr.  85,  no.  138: 

330  ;i53.  fig.  2S2  a>3.     1010. 

Vromycrn  atriatuB  Schrcet;  IWutloprziza  mediraginin  (Lib.)  Sacc;  PhyUo$ticta 
sp;  PUoaphfrrulina  brionuina  Pollarri;  Peronospora  trifoliorum  De  By;  /?Ai- 
loelimia  violarta  Tul;  PnewiomonaB  mniicafjinis;  yellow  top;  stem  cracking 
{Phnma  Hp.  K 

Krrata  note:  V\H\n  statement  of  the  author,  the  geniu)  Phomo|)sis,  p.  330 
and  .'MO,  Hhould  reiul  Phoma. 

Melhus,  Inring  E.,  Rosenbaum,  Joseph,  and  Schultz,  Eugene  S.  S|K)ngos|N>ra 
Hubtorranea  and  l'h(»ma  tulK*n»Ha  on  the  Irinh  potato.     Jour.  .\gr.  Research 

7,  nf».  :>:  213  254,  1  fig.,  pi.  A.  7  14.     OctolMT  .«).  1016. 

Ifash,  George  Valentine.     Injury  to  evergrcenH.     .Jour.  New  York  Bot.  Card.  17, 

nt>.  JSri:  170  lH."i.     OrtolnT.   1016. 
Ifowell,  WlUlam.    The  dying  of  citrus  tn^en:  :i  coinpariHon.     .Agr.  News  [Barbaiios] 

15,  no.  370:  'M\k\'MV:.     N«»v<iii»mt  4.    1016. 
O'Gara,  Patrick  Joseph.    Orcurrcnre  of  yellow  leaf  rust  of  wheat  (Puccinia  gluma- 

runi»  in  thi*  Salt  Lakr  valley,  I'tah.     Science  n.H.  44,  no.  1130:  610-^11.     Octo- 

Imt  27.  1016. 
Pammel,  Louis  Hermann,  King,  Charlotte  M.,  and  Seal,  J.  L.    Studies  on  a  Fusarium 

diM*as4*  of  corn  and  sorglium.     il'reliminary.  j     Iowa  .Agr.  Kxpt.  Sta.  Research 

Bui    :»:  113  VM\.  \:^  fig      1016. 
Litcrattirr  of  corn  ri»tM.  p.  11')  IIH. 
Reimer,  Frank  Charles.    .\  promiiting  new  |>i*ar  ntock.     .Mo.  Bui.  State  Com.  Ilort. 

(California)  6,  no.  :>:  \m  171,  fig.  oO  60.     .May,   1016. 
Pyrua  calUryana.     Very  resistant  to  blight. 


1917]  Literature  on  American  Plant  Diseases  81 

Rumbold,  Caroline.    Pathological  anatomy  of  the  injected  trunks  of  chestnut  trees. 
Proc.  Amer.  Phil.  Soc.  66,  no.  6:  48^-493,  pi.  15-18.    July,  1916. 
Literature  cited,  p.  493. 

Schneider,  Albert.  A  parasitic  saccharomycete  of  the  tomato.  Phytopathology 
6,  no.  5:  39^399,  4  fig.    October,  1916. 

Shear,  Cornelius  Lott.    False  blossom  of  the  cultivated  cranberry.    U.  S.  Dept. 
Agr.  Bui.  444,  7  p.,  4  pi.     1916. 
Literature  cited,  p.  7. 
Cause  not  known. 

Smith,  Clayton  Orville.  Crown  gall  or  plant  cancer.  Mo.  Bui.  State  Com.  Hort. 
[California]  6,  no.  6:  201-211,  fig.  71-72.     1916. 

Smith,  Erwin  Frink.  Tumors  in  plants.  Science  n.s.  44,  no.  1139:  611-^12.  Octo- 
ber 27,  1916. 

Stewart,  Fred  Carlton.  Observations  on  some  degenerate  strains  of  potatoes. 
New  York  State  Agr.  Expt.  Sta.  Bui.  422:  310-357,  12  pi.     1916. 

Stoddard,  £.  M.,  and  Moss,  A.  £.  Cutting  out  chestnut  blighted  timber.  Connecti- 
cut Agr.  Expt.  Sta.  Ann.  Rpt.  1916,  pt.  6:  488-496,  pi.  27-28.    August,  1916. 

Stone,  George  Edward.  Injury  to  vegetation  resulting  from  climatic  conditions. 
Jour.  New  York  Bot.  Card.  17,  no.  202:  173-179.    October,  1916. 

Thorn,  Charles,  and  Currie,  James  N.    Aspergillus  niger  group.    Jour.  Agr.  Re- 
search 7,  no.  1:  1-15.    October  2,  1916. 
Bibliographical  footnotes. 

Tisdale,  W.  H.  A  Melanconium  parasitic  on  the  potato.  Phytopathology  6,  no.  5: 
390-394,  3  fig.     October,  1916. 

Relation  of  soil  temperature  to  infection  of  flax  by  Fusarium  lini.  Phyto- 
pathology 6,  no.  5:  412-413.    October,  1916. 

U.  S.  Department  of  the  Agriculture.    Bureau  of  Plant  Industry.    Report  of  the 
chief,  [19151/16.     18  p.     1916. 
Plant  pathological  investigations,  p.  3-6. 

Federal  Horticultural  Board.    Report  [1915]/16.     14  p.     1916. 

Service  and  regulatory  announcements.    August:  93-101,  September 

30;  September:  103-129,  1  fig.,  November  16.     1916. 

Weir,  James  Robert.  Phacidium  infestans  on  western  conifers.  Phytopathology 
6,  no.  5:  413-414.    October,  1916. 

Pinus  ponderosa  and  P.  jeff'reyi,  hosts  for  Razoumofskya  americana.  Phy- 
topathology 6,  no.  5:  484.    October,  1916. 

Whetzel,  Herbert  Hice,  Hesler,  Lexemuel  Ray,  Gregory,  Charles  Truman,  and  Ran- 
kin, William  Howard.  Laboratory  outlines  in  plant  pathology.  207  p.  Ithaca, 
New  York,  1916. 


[Phytopathology,  for  December,  1916  (6: 419-454)  was  issued  Novem- 
ber 29,  1916.] 


PHYTOPATHOLOGY 

VOLUME  VII  NUMBER  2 

APRIL,  1917 


THE  PERFECT  STAGE  OF  GLCEOSPORIUM   VENETUM 

Walter    PI .   B  u  k  k  h  o  l  d  e  it 
With  Three  Fkjures  in  the  Text 

During  the  oarly  siuniner  of  1914  while  studying  the  anthracnose 
disease  of  the  raspberry  at  Brant,  New  York,  a  peculiar  ascomycete  was 
observed  by  the  writer.  The  fungus  although  not  of  general  occurrence 
was  found  only  in  the  anthracnose  lesions  (fig.  1),  and  arose  from  the 
stroma  of  the  pathogene  GloBOsporium  venetum  Speg.  This  led  to  the 
belief  that  there  was  a  possible  connection  between  the  two  fungous 
fonns  and  a  niunber  of  inoculation  experiments  were  conducted  in  order 
to  verify  this  assumption. 

It  was  difficult  to  obtain  ascospores  for  making  inoculations  owing  to 
the  scarcity  of  the  ascocarps.  Furthermore  the  ascospores  w^ere  borne  in 
the  same  lesion  with  the  conidia  of  Glceosporium  venetum  and  a  separation  of 
the  two  types  of  spores  was  practically  impossible.  It  was  finally  decided 
to  use  spores  from  a  culture  of  the  fungus  developed  from  a  single 
ascospore. 

Several  attempts  were  made  to  isolate  the  fungus.  The  poured  plate 
method  first  employed  was  discarded  later  on  account  of  the  difficulty 
in  obtaining  ascospores  sufficiently  removed  from  the  conidia,  the  latter 
usually  being  in  great  abundance.  A  second  method  and  similar  to  one 
used  by  Barber^  was  also  tried.  This  consisted  in  crushing  the  ascocarps 
in  a  drop  of  sterilized  water  on  a  sterilized  slide.  A  glass  tube  with  a 
bore  of  about  3  mm.  was  drawn  to  a  capillary  tip  at  one  end;  to  the  op- 
posite end  was  fastened  a  piece  of  rubber  tubing  about  40  cm.  in  length. 
The  free  end  of  the  rubber  tube  was  placed  in  the  mouth  and  by  manip- 
ulating the  glass  point  with  the  hand,  spores  could  be  drawn  into  the  bore 
of  the  tube.  The  great  difficulty  in  using  this  method  with  the  fungus 
under  consideration  was  the  fact  that  the  ascospores  were  very  gelatinous 
and  had  a  tendency  to  adhere  to  the  glass  slides,  refusing  to  enter  the 

*  Barber,  M.  A.  On  heredity  in  certain  microorganisms.  Kansas  Sci.  Bui.  4: 
3-48.     1907. 


1917]  Burkholder:  Plectodiscella  veneta  85 

globules  and  pigments  which  give  color  to  the  fungus.  Only  on  rare 
occasions  and  on  media  containing  a  small  percentage  of  agar  do  fila- 
mentous hyphae  extend  for  any  distance  from  the  sclerotia-like  formations. 
This  growth  on  artificial  media  although  identical  with  that  of  (?.  venetum 
is  decidedly  different  from  that  of  any  species  of  Gloeosporiimi  which  has 
a  perfect  stage  belonging  to  the  genus  Glomerella. 

As  the  writer  has  continually  foimd  to  be  the  case  with  cultmres  of  G. 
venetum,  difficulty  was  encoimtered  in  finding  conditions  favorable  for 
the  sporulation  of  the  fimgus.  It  was  finally  observed,  however,  that  a 
sudden  change  in  the  humidity  of  the  cultmre  tube  caused  a  production 
of  conidia  which  were  obtainable  in  sufficient  numbers  for  use.  In  order 
to  effect  this  change  the  fungus  was  grown  on  three-per-cent  potato  agar 
until  large  sclerotia-like  masses  were  formed.  These  masses  were  trans- 
ferred to  sterilized  bean  pods  in  tubes  which  contained  several  centi- 
meters of  water.  The  cultures  were  tiien  incubated  at  a  temperatmre  of 
24°C.  and  at  the  end  of  three  days  numerous  conidia  were  produced  which 
were  identical  with  the  conidia  produced  in  cultmre  by  G.  venetum.  It 
was  also  observed  that  this  sporulation  was  not  continuous,  but  ceased 
after  the  first  production  of  spores.  Fiu-thermore,  a  cultiu*e  of  the  fxmgus 
subjected  from  the  beginning  to  a  moist  condition  produced  no  spores  or 
at  least,  but  relatively  few.  This  apparently  indicates  that  the  sudden 
increase  in  himiidity  acts  as  a  stimulus  to  spore  formation. 

By  dropping  these  fimgous  masses  bearing  conidia  into  a  small  amount 
of  water  the  spores  readily  fall  off  and  can  be  sprayed  over  the  infection 
court.  The  germination  of  these  conidia  is  fairly  rapid,  but  the  percent- 
age of  germination  is  low.  In  most  cases  not  more  than  five  or  ten  per 
cent  of  the  spores  germinate. 

INOCULATION  EXPERIMENTS 

Early  in  the  winter  of  1914  a  nxmiber  of  roots  of  the  Colxmibian  variety 
of  the  raspberry  were  obtained  and  planted  in  the  greenhouse.  Owing 
to  the  earliness  of  the  dormant  period  and  to  the  unfavorable  conditions 
arising  within  the  greenhouse,  the  plants  grew  slowly,  and  gave  a  very 
stxmted  growth.  All  inoculation  experiments  with  these  plants  gave 
negative  results.  The  anthracnose  lesions  appear  only  on  tender  suc- 
culent canes  and  apparently  the  canes  which  had  developed  slowly  on 
the  greenhouse  plants  were  too  hard  for  the  fungus  to  infect. 

Later,  about  the  first  of  March,  1915,  a  few  raspberry  plants  of  a  red 
variety  were  secured  which  were  tender  and  growing  rapidly.  On  March 
4,  two  canes  were  sprayed  with  a  suspension  of  conidia  from  a  culture  of 
the  fungus  developed  from  a  single  ascospore  and  the  canes  were  covered 


86  Phytopathology  [Vou  7 

with  bell-glasses  lined  with  moist  filter  paper.  These  glasses  were  plugged 
at  the  top  with  cotton  and  allowed  to  remain  over  the  canes  for  two  days 
before  removing,  while  two  other  canes  in  the  same  bed  remained  imtreated. 
On  March  20,  small  purple  spots  had  appeared  on  one  of  the  canes.  These 
infections  grew  slowly,  much  slower  than  an  anthracnose  lesion  develops 
under  field  conditions,  but  spots  typical  of  those  caused  by  Gkto^porium 
venetum  were  produced.  Miscroscopical  examination  of  the  spots  showed 
conidia  of  G,  veneium. 

Again  on  April  15,  four  very  tender  canes  of  a  black-cap  variety  of 
raspberry  were  sprayed  with  a  suspension  of  conidia  as  above.  Bell 
glasses  were  placed  over  the  plants  as  in  the  previous  experiments  and  one 
check  plant  was  tised.  A  sample  of  the  conidia  used  was  placed  in  a  drop 
of  water  on  a  slide,  and  about  eight  per  cent  of  the  spores  germinated. 
After  one  week,  April  21,  a  nimiber  of  small  purple  spots  had  appeared  on 
the  four  canes,  and  these  later  developed  into  t>'pical  anthracnose  lesions. 
The  check  plant  remained  healthy. 

THE  DEVELOPMENT  OF  THE  A8CIGEROL8  STAGE 

From  the  positive  results  of  the  inoculation  experiments  and  also  from 
the  examination  of  the  fimgus  in  culture  it  is  evident  that  the  ascomycete 
under  consideration  is  the  perfect  st-age  of  Gkeoftporium  venetum.  The 
8>'stematic  position  of  the  fungus,  however,  is  rather  diflficult  to  determine. 
Its  morj)holog>'  is  entirely  different  from  the  perfect  stage  of  any  species 
of  (ilcDosporium  previously  described.  This,  however,  is  not  siuprising 
as  (7.  veneium  has  always  l)ec»n  considenMl  distinct  from  the  other  species 
of  that  genus. 

The  ascig(»n)us  stage  of  the  fungus  wjis  first  ol)served  on  the  hybrid 
raspl)err>'  commonly  known  as  Kubus  negleclwt.  I^ter  it  was  collecte<l 
in  various  |wirts  of  Ne^*  York  Stati*  on  the  bbick  rasplx»rr>'  (Rubus  occi- 
dentalis)  and  the  American  red  rasplxTry  (Kubus  idceus  var.  aculeaiwimuB) . 
RcHis'  alMo  rei)orts  having  found  it  iti  Washington  on  the  blackl)err>' 
(Rubua  sp.). 

During  the  siunmer  following  the*  discovery  of  the  ascigerous  stage 
clos4»  ol>ser\'ation  was  kept  of  the  fungus  on  th(»  young  canei*  to  detennine 
when  the  Jisconiqw  first  lK»gan  to  <lcv(»lop.  This  pn)ve<l  to  be  about  the 
middle  of  August.  At  this  time  the  fruiting  Inxlies  which  greatly  resemble 
those  in  the  family  Myriangiaceie  apfK^iir  as  minute  s|K)ts,  deep  brown  to 
black,  singly  or  in  grou|>s  s<'attenHl  over  the  huff-colored  and  sunken  por- 
tion of  the  anthracnose*  lesion.     These  spots  an»  Imrely  visible  to  the  €>•« 

*  Rm"^.  H.  L.  Kx|N*nmental  (ipra>nnK  for  hlarkbeiT>'  anthracnose  in  1915.  Watt- 
em  WanhinKton  Kxp.  Sta.  Mo.  Bui.  3*:  1-10.     1915. 


1917]  Burkholdbb:  Plectodiscella  veneta  87 

and  only  so  on  account  of  the  contrast  in  color  with  the  surrounding  tissue. 
After  passing  the  winter  the  entire  lesion  assumes  a  dark  brown  color  and 
then  the  pustules  are  observed  with  great  difficulty  even  with  a  hand  lens. 

A  careful  examination  of  the  diseased  area  upon  which  the  asco  arps 
are  found  proves  it  to  be  a  typical  anthracnose  lesion.  The  buflf-colored 
portion  is  fimgous  tissue,  more  or  less  plectenchymatous  in  structiu'e. 
It  is  composed  of  very  small  hyphae  which  are  difficult  to  distinguish 
imless  carefully  stained  and  it  is  the  same  tissue  from  which  arise  the 
conidiophores  of  the  GlcEOsporixun  stage.  The  ascocarps  arise  from  the 
stroma  and  are  pulvinate  structures  usually  circular  in  outline,  but  they 
frequently  coalesce,  forming  spots  of  various  shapes.  They  are  approx- 
imately 0.07  by  0.07  to  0.37  mm.  in  diameter.  The  tissue  of  the  ascocarp 
is  more  or  less  pseudoparenchymatous  with  larger  and  thinner-walled 
cells  than  those  of  the  stromataceous  tissue  (fig.  2).  The  outer  layer  of 
the  ascocarp  is  composed  of  thick-walled  brown  cells  which  form  a  shield- 
shaped  structiu'e  less  perfect,  however,  than  those  observed  in  the  family 
Microtheriaceffi.  When  the  fruiting  body  is  matiu'e  the  cells  of  this  outer 
layer  split  apart-  in  a  stellate  manner  and  crumble  away.  Within  the 
shield  the  ascocarps  are  hyaline  and  contain  the  asci  which  are  scattered 
irregularly  through  the  fungous  tissue.  There  is  no  differentiated  cavity 
for  the  asci. 

The  asci  were  first  observed  in  the  immature  condition  at  which  time 
they  appeared  as  globose  bodies  containing  a  homogenous  mass  of  proto- 
plasm, and  greatly  resembling  thick-walled  oogonia.  These  asci  may  lie 
in  contact  with  each  other  but  frequently  they  are  separated  by  the  fim- 
gous tissue.  The  mature  ascus  is  thick-walled  and  measures  24  to  30/4 
in  diameter.  In  a  few  cases  the  ascus  has  appeared  to  be  slightly  stalked 
and  attached  to  the  base  of  the  cavity  in  which  it  is  borne. 

In  the  autmnn  or  more  often  in  the  spring  the  asci  matiu-e  and  the 
homogenous  mass  of  protoplasm  gives  place  to  eight  four-celled  ascospores. 
These  spores  which  are  borne  parallel  to  each  other  in  the  ascus,  are  hyaline 
with  gelatinous  walls,  and  constricted  at  the  septa.  The  basal  cell  is  some- 
what more  obtuse  than  the  apical  cell.  The  mature  ascospore  measiu'es 
18  to  21/i  in  length  by  6.5  to  8/u  in  diameter. 

In  the  formation  of  these  spores  the  middle  septum  is  laid  down  much 
earlier  than  the  other  two,  and  for  this  reason  it  is  not  imcommon  to  find 
two-celled  spores.  With  the  division  of  these  cells  giving  rise  to  the 
foiu'-celled  condition,  the  constrictions  are  not  so  great  as  at  the  first 
septimi.  Occasionally  one  of  the  cells  fails  to  divide  and  an  ascospore  of 
three  cells  is  formed.  During  the  formation  of  the  spore  the  disintegration 
of  the  fimgous  tissue  about  the  asci  takes  place  and  with  the  rupturing 
of  the  outer  layer  of  the  ascocarp  the  asci  are  exposed.    Frequently  the 


Phttopatholoot 


[Vol.7 


asci  lying  in  this  exposed  condition  surrounded  by  the  remainder  of  Um 
•scocarp  give  the  appearance  of  a  true  discomycete.  This,  homrer,  is 
duo  to  the  persistency  of  the  outer  cells  of  the  ^eld-like  layer  whidi 


Pia.  2.  «Crou-«iction  or  AscocAxr  or  PLCcrootacsLLA  vbmbta 
Vuioua  itKces  ia  th«  dcrelopmeat  of  the  uci  u«  ■hown 


1917]  Burkholder:  Plectodiscella  veneta  89 

covers  the  immature  ascocarps.  With  the  presence  of  sufficient  moistiu-e 
the  exposed  asci  elongate  approximately  three  times  their  usual  length. 
This  process  is  very  rapid  and  may  be  observed  imder  a  microscope  when 
a  fragment  of  tissue  containing  asci  is  placed  in  a  drop  of  water.  The 
lower  portion  of  the  ascus  remains  fastened  in  the  cavity  in  which  it  was 
borne,  giving  a  conical  shape  to  the  body  which  raises  itself  above  the  sur- 
rounding tissue.  The  spores  gather  at  the  tip  of  the  ascus  and  from  there 
are  ejected  into  the  air.  They  have  been  caught  above  the  lesions  at 
a  distance  of  one  centimeter. 

In  a  single  ascocarp  all  the  asci  are  never  in  the  same  state  of  maturity 
and  the  ascocarps  also  seem  to  vary  in  this  respect.  Mature  ascospores 
were  first  observed  about  the  first  of  Jime  while  inunatiu'e  spores  were 
present  in  August. 

GERMINATION  OF  SPORES 

When  placed  in  tap,  rain  or  distilled  water,  or  on  nutrient  agar,  the 
mature  ascospores  germinate  readily  (fig.  3).  They  swell  somewhat  and 
within  less  than  two  hours  a  short  sterigma  is  produced  from  one  or  each 
of  the  cells.  A  sprout  conidiimi  is  formed  which  is  oblong  to  elliptical 
and  identical  with  the  conidia  of  the  fungus.  When  fuUy  mature  the 
sprout  conidia  drop  from  the  sterigmata  but  do  not  germinate  immedi- 
ately. After  a  short  period  of  rest,  twelve  to  twenty-four  hours,  a  germ- 
tube  is  sent  forth  and  mycelium  is  formed.  When  an  ascus  is  placed  in 
a  drop  of  water  or  on  agar  the  spores  within  TviU  germinate  by  sending  the 
sterigmata  through  the  wall  of  the  ascus  and  produce  the  sprout  conidia 
on  the  outside.  These,  in  turn,  germinate.  After  Ihe  production  of 
the  secondary  spores,  however,  the  ascospores  shrivel  and  disintegrate. 

SYSTEMATIC   POSITION 

The  morphology  of  the  fungus  of  the  raspberry  anthracnose,  especially 
the  character  of  the  asci  scattered  irregularly  through  a  pseudoparenchyma 
is  similar  to  that  of  the  old  family  Myriangiacese.  In  a  revision  of  this 
family  some  years  ago  by  von  Hohnel*  but  five  genera  out  of  twenty-three 
were  retained,  and  since  then  but  one  new  genus,  Ascostralum  Sydow^  has 
been  added.  The  perfect  stage  of  Glceosporium  venetum,  however,  does 
not  appear  to  fall  in  any  of  these  genera,  nor  in  any  of  the  genera  of  closely 

'  Hohnel,  F.  von.  Fragments  zur  mycologie  VI.  Mitt.  244.  Sitzungsber.  M-N 
Classe,  k.  k.  Akad.  Wiss.  Wien.  U8:  349-376.     1909. 

*  Sydow,  H.  von  and  Sydow  P.  von.  Beschreibungen  neuen  sUdafrikanischen  Pilze. 
Ann.  Myc.  10:  41-42.     1912. 


90  Phytopathology  [Vol.  7 

related  families.  More  recently  Woronichin'^  described  a  new  genus, 
Plectodiscella,  based  on  a  single  species  which  he  found  occurring  on  the 
leaves  of  the  apple  and  pear.  This  genus  is  closely  related  to  ELdnce  of 
Raciborski*  butdififers  mainly  in  that  the  stroma  is  not  borne  beneaUi  the 
epidermis.  Plectodiscella  Piri,  the  representative  of  the  genus,  is  so  simi- 
lar in  morphology  to  the  ascigerous  stage  of  GUeosporium  venetum  Speg. 
that  apparently  there  is  a  distinct  relation  between  the  two.  A  brief 
description  of  Woronichin's  species  is  here  set  forth:  A  more  or  less  im- 
perfect stroma  is  formed  in  the  epidennal  and  sub-epidermal  cells  of  the 
leaf,  which  is  at  first  sub-cuticular.  From  this  arises  a  fimgous  tissue  in 
which  are  borne  irregular  globose  asci,  each  containing  eight  four-celled  asco- 
pores.  In  some  instances  the  asci  are  separated  by  the  fimgous  tissue 
and  in  others  they  lie  in  contact  with  each  other.  Woronichin  is  uncer- 
tain as  to  the  nature  of  this  tissue  l>etween  the  asci.  He  says,  **Wa« 
fiir  Elementc  die  z^'ischen  den  Ascen  l)efindlichen  Zwischenraume  ausfQl- 
len,  gelang  es  nicht  genau  aufzuklaren."  He  does  not  consider,  however, 
that  it  is  cellular.  This  is  also  the  first  impression  received  in  regard  to 
the  raspberr>'  fungus,  due  to  the  fact  that  the  cells  are  minute  and  disinte- 
grate very  ejirly.  The  cellular  strticture  of  the  fungus  on  raspberr>' 
was  determined  only  on  young  material  and  then  after  it  was  fixed  and 
8taine<i.  In  Plectodiscella  Piri  a  shield-like  arrangement  composed  of  one 
layer  of  dark  cells  covers  each  ascocarp  and  later  breaks  apart  in  order 
that  the  asci  may  be  ejcposed.  In  the  perfect  stage  of  Glaoiporium  vene- 
turn  this  is  present  but  is  clearly  seen  only  in  the  inmiature  stages  before 
rupturing  occurs.  Woronichin  does  not  refer  to  an  imperfect  stage  for 
his  fungus. 

Plectodiscella  Piri  is  considered  to  be  far  enough  removed  from  the 
MyriangiacesB  or  any  of  its  closely  related  families  to  be  placed  in  a  new 
family.  Tliis,  Woronichin  describes  as  Plectodiscelle®  and  states  that 
it  occupies  a  s>^tematic  position  somewhere  lx»tween  the  Plectascales 
and  the  true  Discomycetes.  Here  he  places  his  fungus  P.  Pin*  but  gives 
no  exact  characters  for  his  genus.  Only  the  family  and  species  are 
descril)ed. 

Taking  all  characters  into  consideration,  the  pcTfcH't  stage  of  GUto- 
sporium  venetum  Speg.  appears  to  belong  to  this  genus  and  therefore  the 
following  name  is  proponed: 

•  Woronichin,  N.  M.  Plertodiscella  Piri,  diT  Vcrtrctcr  einorneuen  ascomyc«teii 
Gnippe     Nfycol.     Centralh.    4:  225-233.     1914. 

*  Harikxirfiki.  M.  Kluiomv  Har.  nov.  f(en.  Parasitiiiche  Algen  und  Pilte  Jara't 
1:  15-16.     IWO. 


1917]  Burkholder:  Plectodiscella  veneta  -91 

Plectodiscella  veneta  sp.  nov. 

Stromattbns  solitariis  vel  gregariis,  pvlvinaiiSy  epidermide  fusca  diacoida, 
mox  dehiscerUe,  intus  contextu  hyalinOf  pseudoparenchymatico  vel  indistincto, 
plerumque  pluriloculigeris,  loculis  monasciSy  irregulariter  sparsis;  dscis 
globosis,  8  sporis,  24rS0n;  sporidiis  ovoideo^llipsoideis,  saepe  flexis,  hyalintOy 
SseptatiSy  canstrictis,  ceUuLa  basilare  cbtusay  18-21  x  6,6  x  8fi. 

Hob,  In  ramis  caulibuaque  vivis  Rvbi  occiderUalis,  R.  idaei  var. 
aculeatissiini  et  R,  neglecti.  New  Yorky  America  bcreale.  Status  coni- 
diaphorus  eat  Glceosporium  venetum  Speg, 

Cornell  University 
Ithaca,  New  York 


PUCCINIA  SUBNITENS  AND  ITS  AECIAL  HOSTS 

Ellsworth    Bkthkl 

Puccinia  subnUens  Diet.  \b  a  common  rust  on  Distichlis  9pieaia  from 
the  Atlantic  to  the  Pacific  coast.  The  telial  host  is  especially  abundant 
in  the  alkaline  soils  of  the  desert  regions  of  the  western  United  States. 
Prior  to  1904,  Chenopodium  album  was  the  only  known  aecial  host  of  this 
rust.  In  the  summer  of  1904,  Rev.  J.  M.  Bates,  from  field  observations 
in  Nebraska,  concluded  that  aecia  on  species  of  Cleome,  Sophia,  Lepid- 
ium,  Erysinuim,  and  Salsola  were  related  to  Pxiccinia  subnilens.  These 
suggestions  iiiTre  conmiunicated  to  Dr.  J.  C.  Arthur,  who  later  in  the 
summer  succeeded  in  growing  the  teliospores  on  these  hosts,  thus  con- 
firming the  deductions  made  by  Bates.  Dr.  Arthur,  in  giving  the  results 
of  these  cultim»s,  remarks  (Joiu*.  Myc.  11:  50-67),  *'\Ve  have  here  a  dem- 
onstration of  the  remarkable  fact,  not  known  for  any  other  species  of 
rust,  that  Puccinia  subniiens  has  aecia  growing  \iith  equal  vigor  on  three 
families  of  plants."  I-.ater,  Arthur  grew  it  on  Capsella  (Bursa)  sp., 
AtripUz  hastataf  and  doubtfully  on  Sarcobaius  sp.  He  has  grown  this 
species  on  nine  or  ten  genera  in  three  families. 

For  ten  >'ears  or  nrort*,  the  writer  has  observed  the  aecia  of  this  rust 
abundant  in  Colorado  on  species  of  Polygonum,  (chenopodium,  Lepidium, 
Capsella,  Cleome,  Salsola,  and  Abronia,  and  in  1912  made  successful  cul- 
tures on  all  of  these  genera  except  Abronia.  During  the  past  summer, 
aecia  which  seemed  immistakably  related  to  Puccinia  subnitens  were 
foimd  on  plants  of  several  other  genera,  and  cultures  were  made  to  de- 
tennine  the  correctness  of  these  observations.  Likewise  all  previous 
cultun»s  i*-ere  repeated  with  the  result  that  the  aecia  were  produced  on 
22  s|MM*ies  in  6  families,  and  15  genera.  The  following  is  a  list  of  suc- 
cessful rtiltures. 

1.  Polygon ACK.*::  Polygonum  aviculare  L.,  P.  erecium  L.,  P.  ramonstt- 
mum  Mirhx. 

2.  ('iiknoi»<>i>ia<k.k:  SaUola  peMiftr  \.  Nc»L*<.,  Chenopodium  album  L., 
r.  ijhiHcxim  L..  r.  Uiiiceolatum  Muhl.,  (\  pagonum  Reich.,  Manoltpi^ 
nutUillittnn  iK.  iV  Sj  (Sreene,  Kttchia  scojmria  (L.)  Roth. 

3.  .\MAliANTHArK.K:  Awaranthu^i  rttroflexus  L.,  A,  blitoides  S.  Wats. 

4.  Ny(  TA<flNArK.K:  Ahnnn^i  fnigrans  S\i\{. 

5.  Ckitikkk.*::  ('apsrlln  liursa-iHistoris  Me<lik..  Lepidium  dmsiflorum 
S<'hnid.,  L.   medium   (ireene.   Erysimum   oHperum    DC.,   Sophia   pinnaia 


1917]  Bethel:  Aecial  Hosts  of  Puccini  a  Subnitens  93 

(Walt.)  Britt.,  Roripa  palustris  (L.)  Bess.,  Thlaspi  arvense  L.,  Sisym- 
brium  aUisaimum  L. 

6.  CAPPARiDACEiB:  Cleomc  semUata  Pursh. 

It  will  be  observed  that  the  above  six  families  constitute  two  groups. 
The  first  four  comprise  a  group  of  contiguous  families,  and  the  last  two 
another  group,  likewise  contiguous  but  rather  remote  from  the  first. 
Mcidium  fumaricLcearum  Kell.  &  Swingle  on  Corydalis  is  probably  ne- 
lated  to  P.  subnitens,  though  no  cultures  were  made.  If  this  connection 
should  be  established  it  would  add  another  family,  Papaveracese,  con- 
tiguous with  the  second  group,  a  total  of  seven  famiUes. 

It  is  not  uncommon  to  find  the  aecia  in  abimdance  on  a  half  dozen  or 
more  host  plants  at  one  place,  and  it  manifests  only  slight  racial  tenden7 
cies,  though  it  seems  to  infect  certain  hosts,  such  as  Thlaspi,  Kochia, 
Monolepis,  Amaranthus,  Roripa,  and  Erysimum  very  sparingly.  The 
aecia  occm*  in  abimdance  on  plants  of  all  other  genera  Usted  above. 

Stanleya  pinnata  (Pursh.)  Britt.  bears  a  large  orange-red  aecium  char- 
acteristic of  P.  subnitensy  however,  this  host  failed  to  become  infected, 
though  seven  cultures  were  made  under  the  same  conditions,  and  with 
the  same  material  that  was  used  in  the  successful  cultures  on  other 
hosts.  Cultures  were  attempted  on  Atriplez  hastata  L.,  A.  canescens 
James,  A.  confertifolia  S.  Wats.,  and  Sarcobatus  vermiculatus  (Hook.) 
Torr.  with  no  results.  Arthur  has  reported  successful  cultures  on  Atrip- 
lex  hcistata  L.  with  teUospores  from  Delaware,  and  on  Sarcobatus  vermi- 
ciUatiLs  (Hook.)  Torr.  with  teliospores  from  Nevada.  The  aecia  on  the 
latter  host,  which  closely  resemble  those  of  P.  subnitens,  are  related 
chiefly,  or  entirely,  at  least  in  Colorado,  to  Pucdnia  Ixixuriosa  Syd.  on 
Sporobolus  airoides  Torr.,  as  has  been  shown  by  the  writer  by  several 
successful  cultures  the  past  season,  both  from  aeciospores  and  teUospores, 
so  that  there  can  be  no  doubt  of  this  relationship.  Further,  many  sow- 
ings of  teUospores  of  P.  luxuriosa  on  the  aecial  hosts  of  P.  subnitens  made 
through  two  seasons  gave  negative  results. 

Mcidium  Abronioe  E.  &  E.  was  described  on  Abronia  sp.  from  Fort 
Collins,  Colo.  Many  cultures  both  in  the  field  and  the  garden  show 
that  it  is  the  aecial  stage  of  P.  subnitens.  It  is  common  on  Abronia 
fragrans  Nutt.  in  Colorado  and  occasionaUy  collected  on  A.  eUiptica  A. 
Nels.,  and  A.  micrantha  A.  Gray. 

Late  in  the  summer  cultm'es  were  attempted  on  Beta,  BUtum,  and 
Portulaca  but  no  infection  resulted,  presumably  for  the  reason  that 
the  teUospores'  had  probably  already  germinated.  Successful  cultures 
were  obtained  on  either  Raphanus,  or  Brassica,  but  the  plants  died  be- 
fore developing  sufficiently  for  determination.  The  aecium  on  Cleo- 
mella,  as  noted  by  Arthur,  also  is  probably  related  to  P.  subnitens.    Cul- 


94  Phytopathology  [Vol,  7 

lures  vnW  lie  made  again  next  Heason  on  Stanleya,  Atriplex,  Corydalis, 
ClmmicUa,  Beta  and  plants  of  some  other  suspected  i^encra,  and  if  these 
prf)vc  to  be  aecial  hosts  of  this  rust,  which  seems  very  probable,  we  shall 
have  a  grand  total  of  more  than  a  score  of  genera  in  seven  families- 
remarkably  large  nimil)er  of  aecial  hosts  for  a  single  species  of  rust. 
Colorado  State  Museum 
Denver,  Colorado 


CONTRIBUTIONS    TO    OUR    KNOWLEDGE    OF    THE    WHITE 

PINE  BLISTER  RUST 

W.     A.     MCCUBBIN 


I.    MODE   OF   INFECTION   ON   THE   PINE 

Only  indefinite  references  to  the  method  of  infection  of  the  pine  by  Cro- 
nartium  ribicola  have  appeared  in  current  literature.  From  these  refer- 
ences one  gathers  the  impression  that  infection  takes  place  through  the 
bark,  and  probably  by  way  of  woimds  or  abrasions.  Having  an  oppor- 
timity  for  studying  a  considerable  nimiber  of  pine  infections  in  1916, 
some  attention  was  given  to  this  point,  and  records  were  made  of  the 
origins  of  cankers  where  such  origins  could  be  determined. 

In  most  cases  the  determination  was  not  difficult,  owing  to  the  fact 
that  in  a  healthy  pine  branch  the  fimgus  spreads  out  from  the  court  of 
entry  in  a  very  regular  and  equal  manner,  and  that  its  progress  is  marked 
by  swelling  or  discoloration  or  both,  or  else  the  cortical  tissue  is  killed  in 
an  equally  radial  fashion.  By  taking  note  of  this  habit  one  can  readily 
locate  the  point  of 'original  infection  in  most  cases,  especially  in  the 
earlier  stages. 

TABLE  1 

Records  of  specific  cases  to  show  mode  of  infection  of  pines  by  Cronartium  ribicola 


LOCALITY  * 


Secords 

Four-mile  Creek 
Cookstown 

Totals 


I>rUMBEH  OP 
INPBCT10.V8 


177 

38 

792 


1007 


ORIGIN'  OF  LBfllON 


IjesJ  fasdcleB 


148 

M 

743 


925 


Wounds 


8 
1 
5 


14 


Undetermined 


21 

3 

44 


68 


Very  early  in  this  study  it  became  apparent  that  the  chief  mode  of 
infection  was  by  way  of  leaf  fascicles  through  the  so-called  short  shoots. 
In  these  pines,  which  were  all  healthy  and  which  grew  in  situations  where 
they  were  fairly  free  from  accidents,  wound  infection  played  but  a  very 
small  part.. 

According  to  the  tabulated  results  about  92  per  cent  of  these  young 
bUster  cankers  originate  in  leaf-bundle  infection.     This  percentage  in- 


96  Phytopathology  [Vol.  7 

eludes  only  those  cases  where  the  point  of  ori|^n  could  be  confidently 
established,  but  it  is  highly  probable  that  a  large  proportion  of  the  num- 
ber listed  as  undetermined  should  also  find  a  place  here,  and  it  might 
not  be  overstepping  the  mark  to  ascribe  at  least  95  per  cent  of  thede 
blister  cankers  to  leaf  fascicle  infection. 

One  may  consider  that  the  sporidia  from  the  currant  leaves  are  lodged 
among  the  bases  of  the  needles  and  from  this  position  can  then  attack  the 
short  shoot  which  bears  these  leaves.  In  a  number  of  instances  a  few  of 
the  leaves  on  such  shoots  were  found  to  be  dead  while  the  rest  of  those  in 
the  fascicle  were  quite  healthy;  in  other  cases  all  the  leaves  in  the  fascicle 
had  l)een  destro>'ed  and  often  the  short  shoot  and  even  a  small  area  in 
the  cortex  at  its  base  were  also  killed.  In  milder  cases,  especially  where 
the  growth  of  the  tree  was  very  vigorous,  the  fungus  did  not  kill  either 
the  leaves  or  the  short  shoot,  but  induced  in  the  latter  a  pronounced 
stimulation  of  growth,  so  that  the  short  shoot  became  enlarged  and 
buU)ous  in  appearance. 

In  these  peculiarities  of  short  shoot  infection  may  lie  a  possible  expla- 
nation of  the  year  of  dormancy  which  so  evidently  obtains  in  a  great  ma- 
jority of  C4u*es.  If.  during  the  summer  after  infection,  the  fungus  pro- 
gresses only  into  the  short  shoot  or  slightly  beyond  it  into  the  adjacent 
cortex,  it  would  l)e  difficult  to  recognize  these  minute  symptoms  and 
then»  would  \h*  the  so-called  dormant  year. 

II.    LIFE   CYCLE   OF  THE   FUNGUS   ON   THE   PINE 

In  general  the  tendency  has  been  to  regard  the  life  of  Cronartium  rtW- 
coln  on  its  pine  host  as  more  or  less  indefinite,  varying  from  one  to  two 
y<»ar8  up  to  six  years  or  more;  that  is,  from  the  time  of  infection  \mtil 
aeria  are  pnxluced  from  one  to  six  years  might  elapse.  In  the  study  of 
this  disea^  in  Ontario  in  1916  evidence  has  come  to  hand  which  indicates 
that  the  fungus  tends  to  reach  the  aecial  stage  in  a  fairly  definite  period, 
but  tliat  this  noniial  course  of  development  may  l)e  shortened  or  length- 
onetl  lMH»ause  of  c<»rtain  favorable  or  unfavorable  factors. 

In  the  Niagara  Penin.»<ula  in  1916  there  were  found  a  numl)er  of  young 
pint*  infections  on  tre<»s  growing  close*  to  black  currant-s,  and  though  these 
currants  have  Innnx  badly  nisted  since  and  incluchng  1914,  there  is  reason 
to  think  tliat  no  nL»»t  was  present  on  them  Ix^fore  that  season.  In  any 
CUM*  no  >«ign  of  infection  was  visible  on  these  pines  in  1915,  although  they 
wen*  ciTtainly  ex]x)sed  to  infection  during  the  previous  year.  Moreover, 
in  the  summer  of  1916  no  (hs4»as<»  was  met  with  on  the  groH'th  of  1915 
although  the.*^»  pines  must  have  n»c(»iv(»(l  infection  in  1915.  On  the  other 
hand,  th<»S4»  five  lots  of  pines  dcvelo|MMi  22.3  infections  in  1916,  all  on  the 


1917]  McCubbin:  White  Pine  Blister  Rust  97 

growth  of  1913  and  1914.  It  seems  reasonable  to  think,  therefore,  that 
during  the  year  after  infection  there  are  no  symptoms  of  a  visible  natxire 
in  infected  pine  branches.  Additional  evidence  on  this  point  recently  has 
been  obtained  from  another  district  (Cookstown,  Simcoe  County,  On- 
tario), where  a  young  nursery  row  of  white  pines  was  severely  infected 
from  black  currants  growing  side  by  side  with  them.  Out  of  the  1412 
blister  cankers  recorded  from  these  rows  not  one  was  found  on  the  growth 
of  1915  although  the  pines  were  certainly  subject  to  infection  in  the 
previous  year.  On  the  twig  growth  of  1914  there  occurred  some  286 
cases,  which  number  gives  a  strong  indication  as  to  the  yearly  infection 
that  might  be  expected  here. 

While  the  above  evidence  from  these  two  cases  is  scarcely  conclusive, 
it  is  sufficiently  extensive  tad  clear-cut  to  warrant  the  assumption  that 
in  the  great  majority  of  cases  the  season  following  infection  is  a  "dor- 
mant" year. 

When  the  character  of  all  the  509  infections  recorded  above  is  examined 
further  another  point  becomes  clear.  With  one  exception  all  of  these 
cankers  were  in  what  might  be  termed  the  swelling  stage,  the  cortex  being 
typically  swollen  into  a  spindle  and  usually  discolored.  If  these  cankers 
can  be  taken  to  represent  the  normal  course  of  the  disease,  and  since  they 
include  all  the  infections  foimd  on  the  1914  twigs  of  these  quite  normal 
trees  there  seems  to  be  no  reason  why  they  should  not  be  so  considered, — 
then  the  third  season  of  the  diseare  is  apparently  characterized  by  the 
appearance  of  the  first  visible  symptoms,  the  swellings  just  mentioned. 
And  if  the  formation  of  aecia  from  these  swellings  be  assumed  to  take 
place  during  succeeding  years  a  fairly  normal  life  cycle  will  have  been 
obtained.  Summarized  it  would  run  thus:  first  season,  infection  in  summer 
and  autumn;  second  season,  dormant  period;  third  season,  swelling  stage; 
fourth  season,  aecia.  There  is  evidence,  however,  that  in  the  majority 
of  cases  the  swelling  stage  may  last  for  two  years  before  the  production  of 
aecia.  This  evidence  has  been  obtained  partly  from  the  Cookstown  case 
already  mentioned  and  partly  from  the  Secord  case  where  177  swellings 
were  found  in  1916  on  yoimg  pines  growing  close  to  black  currants. 
When  these  177  swellings  were  arranged  in  a  curve  representing  the 
number  of  them  that  had  occurred  on  each  yearns  growth  it  was  found  that 
the  apex  of  the  curve  came  in  1914;  that  is,  there  were  more  infections 
on  the  growth  made  in  1914  than  on  that  of  any  other  year.  WTien  a 
curve  was  prepared  similarly  from  the  data  obtained  at  Cookstown,  it 
was  of  another  type,  having  the  largest  number  of  swellings  on  the  growth 
of  1913  (fig.  1).  The  nature  of  this  curve  thus  suggests  very  strongly 
that  the  swelling  stage  may  ordinarily  last  two  years  before  the  aecia  are 
produced. 


98  Phttopatholoot  (Vol.  7 

It  is  to  be  noted  that  the  Cookstown  curve  repreaenta  infectiotu  begun 
in  several  successive  yean  vhile  the  Secord  curve  contains  infections  of 
only  one  year,  that  of  1914.  An  attempt  was  made  to  compare  the  two 
wries  of  results  on  a  basis  of  something  like  equality  by  supposing  that 
in  addition  to  the  infections  started  in  1914  in  the  Secord  case  a  similar 
series  of  infections  had  begun  in  1913.  Assuming  that  the  mrellings 
which  would  presumably  arise  from  these  earlier  infections  in  1915, 
would  still  remain  in  the  same  stage  during  1916,  a  curve  was  then  con- 


Kor  expluiation  hc  text 

Hlnirtt^d  which  would  iiicluili'  thif>  h\-iMtthetiiial  xeriem  of  cankers  along 
with  those  sc-tually  pn^etit.  Surh  a  cnrw  would  contain  the  infections 
of  two  uur«*iwiv(*  ypiirf  and  would  ihuo  n-wniblo  ver>-  closely  the  Cooks- 
town  i-urvc.  When  the  ntmilxTs  in  thi!<  n-conmnicted  curve  were  doubled 
in  order  1o  obtuiii  ii  In-ttcr  roin|K>ri.-«m  with  the  Cookstown  curve,  it  was 
Bc«>n  thsit  fxcppt  for  minor  irreKularities  the  two  ('iir\'C!'  are  practically 
iilcnticul. 

The  Won*-  coiicordiuici:  of  this  sup)x>«'d  ciiw  with  the  results  of  the 
Hctiud  :tiir\'py  prrtvidc:*  n  xtrikinK  confinimtion  of  the  indication  already 


1917] 


McCubbin:  White  Pine  Blister  Rust 


99 


given  in  the  Cookstown  curve  of  the  continuance  of  the  swelling  stage 
for  two  years. 

The  evidence  may  be  presented  in  another  way,  by  following  the  course 
of  the  disease  year  by  year  in  a  number  of  shoots  of  1911,  exposed  as  in 
the  Cookstown  case  to  a  more  or  less  constant  annual  infection  from  cur- 
rants. The  number  of  infections  started  in  these  pine  twigs  in  1911  may 
be  represented  by  X,  those  started  in  1912  by  7,  and  those  in  1913  byZ. 
Later  infections  may  no  doubt  take  place  in  these  shoots,  but  smce  the 
number  of  such  infections  is  known  from  other  considerations  to  be  very 
small,  they  may  be  neglected  for  the  purpose  in  view.    A  small  letter 

table  2 
Probable  development  of  the  blister  rust  in  pine  branches  based  on  a  four-years  eyeU 


TSAR 

TBARLT  PBOOBE8S  OW 

NXTMBSR  OF  8WKLLIN08 

ESTIlf  ATBD  PBOPOB- 
TIONB  BASED  ON  BBCOBD 

COOKSTOWN  SUBYBT 

DISBA8B 

PBRSENT  BACH  TXAB 

CA8B 

rXGUBBS 

1911 

X* 

0 

0 

0 

1912 

X^-fY* 

0 

0 

0 

1913 

x'+yd-hz* 

X 

300 

286 

1914 

XHY»+Z<* 

Y 

100 

390 

1915 

Xb_|.Y»>+z« 

Z 

10 

83 

1916 

X*>+Y*>+Z»> 

0 

0 

22 

TABLE  3 

Probable  development  of  white  pine  blister  rust  in  pine  branc?ies  based  on  a  five^ffears 

cycle 


TBAB 

TBABLT  PBOOBX88  OP 
DBUASB 

NDMBBB   OP  SWBLLINaS 
PBBSBNT  BACH  TBAB 

ESTIlf  ATBD  PBOPOB- 

TIONS  BASED  ON  SECOBD 

CASE 

COOKSTOWN  SUBTBT 
nOUBBS 

1911 

x* 

0 

0 

0 

1912 

X**+Y* 

0 

0 

0 

1913 

X-+Y<i-fZ» 

X 

300 

286 

1914 

X"+Y»+Z<» 

X+Y 

400 

390 

1915 

X»»+Y-+Z« 

Y+Z 

110 

83 

1916 

xHy»»+z- 

z 

10 

22 

attached  to  each  of  these  symbols  conveniently  indicates  the  stage  of 
development,  as:  t,  infection  year;  d,  dormant  year;  «,  swelling  stage;  6, 
blister  or  aecial  stage. 

Using  these  symbols  the  accompanying  tables  have  been  constructed 
showing  the  development  of  the  cankers  on  these  twigs.  The  first  table 
is  based  on  a  four-years  cycle,  where  the  swelling  stage  lasts  but  one  year 
before  aecia  are  formed,  while  the  second  table  is  based  on  a  five-years 
cycle,  where  the  swelling  stage  is  continued  for  two  years.  In  the  third 
column  of  both  tables  are  entered  the  number  of  swellings  which  will 


100  Phytopathology  [Vol.  7 

appe:ir  oiich  year,  exprefwed  by  the  h>tii1)oIs  adopted.  An  attempt  hai« 
lKH»n  made  in  the  fourth  eolumn  to  substitute  values  for  X,  }',  and  Z. 
bailed  on  the  proportions  obtaining  in  the  Secord  case.  In  the  Second 
series  the  infections  Ix'gun  in  1914  on  the  growth  of  1914,  1913  and  1912 
were  127,  49,  0.  corresponding  to  X,  y,  and  Z,  respectively.  Adopting 
JiOO  as  an  arbitrar>'  value  for  X,  then  Y  Incomes  approximately  100. 
Z  should  then  be  zero,  but  since  there  is  good  reason  to  think  that  in- 
fections sometimes  occur  on  shoots  of  three  years'  standing,  though  none 
were  foimd  in  this  case,  a  nominal  value  of  10  has  \iecn  assigned  for  Z. 

Beside  these*  estimated  pro)X)rtions  in  the  adjoining  column  are 
placed  the  actual  figures  of  the  C'ookstown  sxirvey.  Since  these  figures 
indicate  th(»  swellings  noted  at  one  time  on  several  successive  years  of 
gn)wth.  they  may  l)e  used  fairly  to  represent  the  swellings  that  would 
aris<»  on  one  y(»jir's  growth  in  a  numlK»r  of  successive  seasons.  It  will  Iv 
MH^n  at  a  glance  tlmt  while  the  estimated  pn)portions  as  obtained  from  the 
figures  of  tin*  S<'C()rd  case  do  not  agrc^c  at  all  with  tho  actual  siu^ey  fig- 
ures in  the  tabic*  showing  a  four-yt^ars  cycl(».  there  is  a  strong  re««em- 
blance  lK»tww»n  thes<»  simie  two  cohunns  in  tin*  tabic*  whore  a  five-yean* 
cvcle  is  us<m1. 

It  is  probable*.  then*fore,  that  tlu^  tal)le  giving  a  five-years  cycle  ex- 
pn»ss<*s  mon*  nc*arly  the  actual  dc»v«»l()pment  of  the  disease  than  the  table 
giving  a  four-yc»ars  cycle;  in  oth(*r  words,  the  nonnal  blister  infection  on 
thc»s<*  young  pifH*s  passi*s  two  yc»ars  in  the  sw(*lling  stage,  and  the  dcvel- 
opni(*nt  of  the  <liM*ase  as  a  whole  follows  this  cours<*:  First  season,  inflec- 
tion;  s<*cond  s<*ason,  donnant  jK*riod;  third  s<»as4)n,  sw(*lling  stage;  fourth 
si'ason,  swc'lling  stiige;  fifth  and  following  s<*ju<ons,  ac*cia. 

The  actuid  time  c*lapsing  l)etw(*c*n  inf(*ction  and  the  first  production  of 
blisti*rs  acconUng  to  this  plan  of  development  is  something  short  of  four 
vears,  but  sin<*e  the  course*  of  the*  dis<»aM*  involv<*s  five*  s<*asons  it  seems 
lM*tt<*r  for  ])ractical  n*asons  to  dc*signatc»  it  as  a  fiv<*-yc*tirs  cycle. 

The  alxive  conclusions  as  to  the  course*  of  development  of  the  dis<»jise 
on  young  pin«*s  should  Ik*  fairly  trustworthy  inasmuch  as  thc*y  an*  Iwiseei 
on  a  fiin^id«TaM«*  numlH*r  of  blister  cankers.  On  the  other  hand,  then*  i* 
certain  rvidftifc  in  Uith  the  (Nnikstown  an<i  the  Se*cord  cas<*s  which  in- 
dicates that  priTocious  or  delay«*<l  devc*lopmi'nt  may  occur,  and  that 
wliilt'  tln'  lif4'-4-vcIc*  (outlined  mav  o!)tain  in  the  majoritv  of  cas<*s,  it  is  bv 
no  m<*ans  to  \h*  n*garde<i  as  an  invariable*  nili*. 

Division  of  Botany 

Dkpartmknt  of  A<iiiiri  i/rriiK 
OrrAWA.  Canada 


SPECIES  OF  MELAMPSORA  OCCURRING  UPON  EUPHORBIA  IN 

NORTH   AMERICA 

E.   B.   Mains 

No  species  of  Melampsora  on  Euphorbia  was  known  to  occur  in  the 
Western  Hemisphere  until  the  present  year.  Collections,  however,  have 
been  made  recently  in  the  United  States  both  upon  introduced  and  native 
species  of  Euphorbia.  These  collections,  which  Dr.  J.  C.  Arthur  has 
kindly  turned  over  to  me  for  study,  consist  of  one  collection  upon  Eu- 
phorbia eommutata  Engelm.  from  Indiana,  four  upon  E.  robusta  Small  from 
Colorado  and  Wyoming,  and  one  upon  E.  Cyparissids  L.  from  Maine. 
Of  these,  it  appears  certain  that  the  one  on  E.  Cyparissias  is  introduced 
and  those  upon  E,  robusta  and  E.  commutaia  are  native. 

Up  to  the  present  time,  six  Old-World  species  of  Melampsora  upon 
Euphorbia  have  been  recognized,  these  being  M,  Gelmii^res,,  M.  Eup- 
horbicB-diUcis  Otth,  M.  Euphorbice-Gerardianoe  W.  Miiller,  M,  HelioscopicB 
(Pers.)  Wint.,  M,  Euphorbiw  (Schub.)  Cast,  and  M,  Euphorbice-Engleri 
P.  Henn.  all  of  which  have  very  similar  uredinia  and  urediniospores, 
the  separation  being  by  telia  and  teliospores.  Of  these  the  first  three 
are  well-marked  and  distinct  species.  Of  the  last  three,  3f .  Helioscopice 
and  M.  Euphorbias  while  distinguished  from  the  rest  by  well-marked  char- 
acters, are  separated  from  each  other,  according  to  Miiller  (1907)  only 
by  a  rather  small  difiference  in  the  length  of  the  teliospores.  This  dif- 
ference may  be  a  real  one  but  is  scarcely  apparent  in  such  European  ex- 
siccati  of  the  two  rusts  as  the  author  has  at  his  disposal  for  examination. 
The  last,  M.  Eurphorbice-Engleri  is  a  species  of  doubtful  validity.  It  was 
set  apart  by  Hennings,  owing  to  its  habit  of  maintaining  itself  wholly  by 
the  uredinia,  other  spore  forms  never  having  been  found.  This  is  only 
known  on  one  species  of  host. 

A  study  of  the  North  American  collections  of  1916  shows  that  they 
can  be  readily  placed  in  three  species,  two  of  which  correspond  to  two 
of  the  above  and  one  of  which  appears  to  be  imdescribed.  The  Maine 
collection,  which  is  upon  Euphorbia  Cyparissias,  has  teliospores  which 
in  length  and  imiform  thickness  of  wall  agree  very  well  with  M.  Euphor- 
bice  upon  the  same  host  ih  Europe,  while  the  Indiana  collection  upon  E. 
eommutata  with  its  31-58^*  long  and  apically  thickened  (3-6/i)  teliospores 
agrees  very  well  with  European  material  of  M,  Euphorbioe-GerardiaruBy 


•  ••    •      •••II     .      ••!:••. I.. •-•• 

• 


102  Phttopathologt  [Vol.  7 

the  uredinioeporee  of  all  being  similar.  The  collections  upon  Euphorbia 
robiuia  from  Colorado  and  Wyoming,  however,  are  distinguished  from  all 
other  species  of  Melampsora  upon  Euphorbia  by  certain  characters  of  the 
uredinia  and  uredinioepores  and  are  considered  by  the  writer  as  belong- 
ing to  an  undescribed  species. 

The  North  American  species  of  Melampsora  upon  Euphorbia  may  be 
keyed  out  as  follows: 

Uredinioepores   1&'23m    long,    paraphyses 
numerous 
Teliospores  decidedly  thickened  at  the 

apex 13/.  Euphorhia-Gerardiana, 

Telioepores  not  or  only  slightly  thick- 
ened at  the  a|>ex 2  M.  Euphorbia, 

Urediniospores  16-29 m  long,  paraphyses  few.. 3  3/.  moniicola. 

I.  Melampsora  EuphorbuB-Gerardiance  W.  Miiller,  Contr.  Bakt.  17*:  210. 
1906. 

O  and  I.  P>''cnia  and  aecia  \mknown. 

II.  Uredinia  amphigenous  and  caulicolous,  scattered,  circular,  0.2-0.5 
mm.  in  diameti'r,  sul)epidermal,  soon  naked,  pulverulent,  pulvinate  due 
to  the  crowded  paraph>Tje8,  pale  yellow,  ruptured  c»pidermis  inconspicu- 
ous; paraph>"Be8  numerous,  intermixed  with  the  spores,  capitate,  16-19 
by  51  58m,  the  wall  colorless,  2-3^  thick;  urediniospores  globoid  to  ellip* 
soid,  13  16  by  16-20m;  wall  colorless,  2-3m  thick,  finely  and  closely  echinu- 
late,  the  por(»8  ol>8cure. 

III.  Telia  caulicolous,  prolxably  also  amphigenous,  circinating  about  the 
uredinia,  oblong,  0.2  1  mm.  long,  8ul)epidennal,  slightly  elevated,  blackish- 
brown;  teliospores  prismatic,  9-15  by  31-60m,  rounded  at  both  ends;  wall 
light  chestnut-brown,  darker  towards  the  apex,  1.5/i  thick,  3-6m  at  the 
apex. 

On  EuPHORBiAcnSiB 

Euphorbia  commulata  Engc^lm.,  West  side  of  High  Lake,  Noble  Co., 
Indiana,  June  11,  1916,  II,  III,  C,C.  Deam  2008SA,  communicated  by 
G.  N.  Hoffer. 

This  collection,  which  is  the  first  collection  of  a  Melampsora  upon 
Euphorbia  to  be  refxirted  for  North  America,  has  a  range  in  the  length 
of  the  teliospore  somewhat  less  than  that  given  by  MQller  (1907,  p.  641) 
for  M.  Eupharbict-Gerardiantt  in  Europe.  A  comparison  with  European 
material  upon  E.  falcata  (Sydow  I'red.  no.  1G87)  sho^-s  a  very  close  agree- 
ment, however,  Uith  as  to  the  ure<iinio8|x)res  and  teliospores.  The  telio- 
spores are  not  quite  so  generally  thickened  at  the  apex  as  in  the  E^uropean 
specimen  but  Mill  are  very  (ie<'ide<lly  thickened,  up  to  3-6^,  while  the 
ure<iinia  have  the  umiuiI  pulvinate  apiieanincc  and  abundant  paraphyses. 

Pvcnia  and  aecia  arc  not  known  for  this  8|>ecics  Init  will  doubtless  l^e 
fouml  upon  the  same  host,  since  M.  Hdioscopue,  M,  Euphorbia  and  M 


1917]  Mains:  Melampborab  on  Euphorbia  103 

EupharbiaHivlcis,  the  three  species  of  Melamspora  upon  Euphorbia  whose 
pycnial  and  aecial  stages  are  known,  are  autoecious. 

2.  Mdampsora  Euphorbice  (Schub.)  Cast.  Observ.  Myc.  2: 18.     1843. 
Uredo    Euphorbice-HelioscopicB  Pers.    p  Euphorbim-exigiUB  Pers.    Syn. 

Fung.  215.     1801. 

Xyloma  (Placuntium)  Euphorbice  Schubert  in  H.  Ficinus  Flora  der 
Gegend  urn  Dresden  2:  310.     1823. 

Uromyces  verrucipes  Vuill.    Bull.  Soc.  Bot  France  41:  285.     1894. 

Mdampsora  Eup}iorbiaS''€xigiuBW.  Muller,  Centr.  Bakt.  IT*:  210.     1906 

Melampsora  EuphorbuB-Pepli  W.  Muller,  Centr.  Bakt.  VP:  210.     1906. 

Mdampsora  EupJiorbuB-CyparissicB  W.  Muller,.  Centr.  Bakt.  19*:  453. 
1907. 

Mdampsora  Cyparissias  W.  Mttller,  Centr.  Bakt.  19*:  561.    1907. 

O.^  Pycnia  flattened  hemispherical;  ostiolar  filaments  none. 

I.  Aecia  foliicolous  and  caulicolous,  circular  to  oblong,  0.2-0.5  mm.  in 
diameter  on  the  leaves,  1-4  mm.  long  on  the  stems,  orange-yellow,  with- 
out peridium  or  paraphyses;  aeciospores  spherical  to  ellipsoid,  19-24  by 
21-28m;  wall  closely  vemicose. 

II.  Uredinia  amphigenous  and  caulicolous,  scattered,  circular  or  oval, 
0.1-0.3  nwn.  long,  early  naked,  pulverulent,  pulvinate  from  the  mass  of 
paraphyses,  golden-yellow  fading  to  white,  ruptured  epidermis  inconspic- 
uous; paraphyBes  intermixed  with  the  spores,  numerous,  capitate,  16^20 
by  31-51/*;  wall  colorless,  3-4/*  thick,  smooth;  urediniospores  globoid  to 
ellipsoid,  13-19  by  17-23/i;  wall  colorless,  2-3/*  thick,  closely  and  finely 
echinulate,  the  pores  obsctu'e. 

III.  Telia  amphigenous  and  occasionally  cauUcolous,  scattered,  cir- 
cular to  oval,  small,  0.1-0.2  mm.  long,  covered  with  the  epidermis,  com- 
pact, pulvinate,  dark  chocolate-brown;  teliospores  prismatic,  7-13  by 
32-45/*;  wall  chestnut-brown  above,  lifter  below,  1-1.5/*  thick,  not  thick- 
ened at  the  apex,  smooth. 

On  EUPHORBIACEiE 

Euphorbia  Cyparissias  L.,  Bank  near  Turner  graveyard.  Isle  au  Haut, 
Maine.    Sept.  13,  1916,  II,  iii,  J,  C.  Arthur. 

3.  Melampsora  monticola  sp.  nov. 
O  and  I.  Pycnia  and  aecia  unknown. 

II.  Uredinia  amphigenous  and  caulicolous,  scattered  or  in  circular 
groups,  circular  or  oblong,  0.2-2  nun.  long,  subepidermal,  long  covered 
by  the  epidermis,  pulverulent,  orange-yellow,  ruptured  epidermis  con- 
spicuous; paraphyses  few,  intermixed  with  the  spores,  capitate,  13-21 
by  32-58/*,  the  wall  colorless,  1.5-3/*  thick,  smooth,  the  stipe  solid;  ured- 
iniospores globoid,  ellipsoid  or  obovoid,  13-20  by  16-29/*;  wall  colorless, 
1.5-3/*  thick,  finely  and  closely  echinulate,  the  pores  obscure. 

III.  Telia  amphigenous  and  caulicolous,  circinating  about  the  uredinia, 
circular  or  oblong,  0.1-1  mm.  long,  subepidermal,  slightly  elevated,  black- 
ish-brown; teliospores  prismatic,  9-16  by  27-56/*,  rounded  at  both  ends; 

^  DeBcription  of  pycnia  and  aecia  adapted  from  Dietel  (1895). 


104  Phytopatholoot  [Vol.  7 

wall  liRht  choatnut-brown  below,  darker  towards  the  apex,  1.5-^  thick, 
2-4m  at  the  apex. 

On  Euphorbiace.c: 

Euphorbia  robusta  Small,  Carpenter,  Wyoming,  Aug.  18,  1916,  II,  iii» 
E,  T,  A'  E,  Bartholomew  6067  {Vromyces  Tranzschelii  Sydow,  0,  III, 
also  present);  (Colorado  Springs,  Colora<lo,  plains  10  miles  east  of  citv, 
Aug.  31,  1916.  II,  iii,  E,  Bartholomew,  6104  (U-pe);  Palmer  Lake,  Colo.. 
Sept.  23,  1916,  II,  III,  E,  Bethel  (two  collections). 

In  the  younger  uredinia,  es|>ccially,  apparently  thinner  walle<l  uredi- 
niosjK)res  are  often  seen  mixed  with  the  thicker.  After  treatment  with 
lactic  acid,  which  serves  to  differentiate  the  wall  from  the  cell  contents 
an<l  make  it  stand  out  more  clearly,  the  apparent  difference  is  not  to  \yc 
()l)serve<l. 

This  species  is  distinct  from  other  sjx^iMes  of  Melampsora  on  Euphorlmi. 
The  unuhnia  are  abundant,  large,  and  long  covered  by  the  epidermis 
and  since  they  (*ontain  l»ut  few  paraphyses,  after  the  rupture  of  the  cover- 
ing epidermis  and  the  cscajM*  of  the  pulverulent  mass  of  sywres,  they  |x>s- 
sess  a  Hattcnc(i  ap|H*arance  when  contnusted  with  the  pulvinate  mass  of 
paraphys(\s  (»f  other  species  on  Kuphorbia.  The  uretUnicxspores  are  much 
more  variable  and  larger  in  size  than  those  of  the  other  si)ecies. 

No  pycnia  or  aec'ia  were  found  uiwn  any  of  the  collections.  They  are. 
how(»vcr,  to  be  lcK»ked  for  upon  the  same  host  earlier  in  the  season  since 
the  rusts  of  this  group  whose  life  cycl(»  an*  known  are  autoecious  with  all 
.sjMin*  forms,  although  Jacky  (1899)  working  with  M.  Euphorbict  on  E 
CypariMsias  and  Muller  (HK)7  p.  449)  working  with  the  same  rust  on  E 
Peplus  claim  to  have  obtained  urtnlinia  by  infection  from  teliospores,  yet 
Dictcl  (189'))  working  with  M.  Enphorbuv  on  E.  Cifparisitias.vLml  Muller 
(19t)7)  with  the  same  rust  on  E.  exigun  on  the  other  hand  have  shot^ii 
that  pycnia  and  ac4'ia  are  prcwluce*!  ujk)!!  these  hosts  from  infections  with 
the  telio^|M»rcs.  Dictcl  (1S89)  has  also  shown  that  M.  Euphorbitr-dulci* 
Srhr<H»t.  has  pyniia  and  aecia.  Since  th(»sc  stages  ar(»  develo|HMl  sparing- 
ly, it  is  probable  that  the  first  workers  overlcH)ked  them  and  that  M. 
Euphurhyt  has  all  s|H)r(»  f<»rms.  Although  all  the  North  .\merican  col- 
lections wcf(»  <»xamincd  for  pycnia  a.ssociate<l  with  the  uredinia  none  were 
found,  and  it  is  pn»bablc  that  all  of  thc.^'  rusts  will  Ih*  found  to  lie  autoe- 
cious and  have  all  s|>*jrc  fonns. 

It  is  interesting  to  note  that  from  a  region  in  which  this  group  has  hith- 
erto not  U»en  kiiowti  so  many  collect i<»ns  from  such  widely  separated 
are.is  should  have  all  Ihm^u  made  in  one  season.  It  is  not  so  surprUing 
that  ^f ,  EupKnrhitr  should  Ik*  f(»und  u|M)n  E.  ('ifpnrissias.iis  the  latter  has 
lieeii  brought  into  this  country  from  Kuro|N*  and  it  is  likely  that  the  rust 
was  intnMlue<Ml  with  it.  It  is,  however,  surprising  that  the  rust 
han  not  previously  U»<»n  foimd  sim»<*  the  host  is  rather  widely  distributed. 


1917]  Mains:  Melampsorae  on  Euphorbia  105 

The  other  two  species  of  Melampsora  are  upon  native  species  of  Euphor- 
bia and  of  these  M,  monticola  is  evidently  a  purely  American  species 
found  upon  a  common  western  Euphorbia.*  With  its  abimdant,  large, 
orange-yellow  uredinia,  it  is  remarkable  that  this  very  striking  rust  has 
not  been  collected  before.  The  other  species,  M.  Euphorbiae-Gerardianae, 
is  probably  native  to  this  country'  as  well  as  to  Europe,  since  its  European 
hosts,  E.  Gerardiana  and  E,  falcata  are  not  known  in  this  coimtry.  An- 
other argument  in  favor  of  this  assumption  is  that  the  species  of  Mel- 
ampsora on  Euphorbia  have  in  most  cases  physiological  races  limited  to 
one  species  of  host  as  Miiller  (1906,  1907)  has  shown.  Consequently 
even  if  European  hosts  were  foimd,  it  would  be  doubtful  if  rusts  on 
American  species  could  be  considered  as  having  an  European  origin. 

The  writer  wishes  to  express  his  deep  appreciation  to  Dr.  J.  C.  Arthur 
and  Prof.  H.  S.  Jackson  for  the  helpful  suggestions  and  criticism  re- 
ceived in  the  preparation  of  this  paper. 

Purdue  University  Agricultural  Experiment  Station 
Lafayette,  Indiana 

literature  cited 

DiBTEL,  p.     1889.    Ueber  die  Aecidium  von  Melampsora  Euphorbiae-dulcis  Otth 

und  Puccinia  silvatica  Schrot.  Oesterr.  hot.  Zeitschr.  N.  7. 

1895.    Ueber  den  Generationswechsel  von  Melampsora  Helioscopiae  und 

M.  vcrnalis.    Forstl.  nat.  Zeitschr.  6:  373. 
MttLLER,   W.     1906    Versuche  mit  Uredineen   auf   Euphorbien   und   Hypericum. 

Centr.  Bakt.  17*:  210-211. 

1907.    Zur  Kenntnis  der  Euphorbia-bewohnenden  Melampsoren.     Centr. 

Bakt.  19*:  441-460,  543-563. 
Stdow,  p.  and  H.     1914.    Monog.  Ured.  3:  379. 
Jacky,    E.     1899.    Untersuchungen   iiber   einige    schweizerische   Rostpilze.     Ber. 

schweiz.  bot.  Gesellsch.  9:49-78. 

*  In  a  commimication  recently  received  from  Mr.  E.  Bethel  he  says,  **The  one 
[Af .  tnarUicola]  we  have  here  is  undoubtedly  native  as  I  found  it  in  the  high  moun- 
tains (above  9000  feet)  at  Nederland,  Colo." 


RECENT  CULTURES  OF  FOREST  TREE  RUSTS 
James  R.  Weir  and  Ernest  E.  Hubert 

The  determination  of  various  species  of  rusts  found  on  forest  trees  ol 
the  general  region  of  Montana  is  a  difficult  task  when  descriptive  evi- 
dence and  spore  measurements  are  used.  In  most  cases  involving  heter- 
oecious  rusts  successful  inoculation  is  considered  very  necessary  in 
determining  the  identity  of  the  species  imder  consideration.  Conse- 
quently, as  a  beginning,  an  attempt  was  made  early  in  March,  1916,  to 
secure  various  forms  of  hypertrophy  formed  by  the  bark-inhabiting  Peri* 
dermia.  After  collecting,  these  were  placed  in  the  laboratory  in  large 
test-tubes  with  sufficient  water  to  supply  the  branch  or  twig  supporting 
the  infection.  Many  needles  were  always  left  on  the  branches  or  twigs. 
In  this  manner  the  fungus  in  many  of  the  infections  was  induced  to  pro- 
duce Hpores  prematurely  and  these  were  available  for  cultiu^  work  at  an 
early  date.  This  process  also  served  to  develop  successfully  the  pycnial 
stage  of  Cronartium  coUasporaides  (D.  A  H.)  Arth.  and  Cronartium 
CompUmia  Arth.  which  stage  preceded  the  aecial  stage  in  both  cases.  In 
the  search  for  material  a  foliicolous  rust  on  the  needles  of  Larix  oecidentaU$ 
was  collected  for  the  first  time  in  June,  1916,  at  various  points  in  Mon- 
tana and  Idaho.  The  rust  was  very  abundant  and  widespread.  All  the 
caulicolous  forms  of  rusts  on  forest  trees  in  this  region  and  in  the  states 
of  Michigan  and  Minnesota  as  well  as  a  number  of  the  foliicolous  forms 
were  tried  on  a  variety  of  suspected  hosts.  All  inoculations  were  isolated 
at  the*  gnrnhoui^  at  Missoula,  Montana,  by  the  use  of  celluloid  cylinders 
and  (*otton  plugs.  The  inoculated  plants  were  sprayed  daily  with  tap 
water  for  a  period  of  throe  to  five  days  following  inoculation.  The  fol- 
lowing is  a  summar>'  of  the  cultures  to  date  since  the  last  report.^ 

Five  pbmts  of  Casiilleja  angusiifolia,  two  on  May  14,  1916,  and  three 
on  May  8,  1916,  were  dustiMl  with  nei^ly  develo|)ed  neciospores  (forced 
in  lnl>orator\')  of  Cronartium  coleosporoidea  (D.  A  11.)  Arth.  (P.  siatacU- 
fimne  ty|M»)  on  Pinus  cofUorta  from  Hayden  I^ike,  Idaho.  Of  the  first 
two  plant.**  one  di-v(»lojMMl  uredinia  on  May  26  and  telia  on  May  29,  the 
n*n)aininf(  plant  dyin^  lK»fore  May  24.     ()f  the  other  three  plants,  two 

'  W«*ir.  J.  H..  And  Iltibort.  K.  K.  SuocoAflful  inorulationfl  of  Larix  occidentalit 
an<l  Larix  curo|N*a  with  Mclainp^ira  l>ifcolowii.     Phytopath.  6:  372-373.     A^.     1016. 

Weir.  J.  H.  and  HiilHTt.  K.  K.  .\  ftucccHsful  inonilation  of  Abien  lantocarpa  with 
PurriniaMtruin  pustulatuni.     Phytopath.  6: 373.     Ag.     1916. 


1917]  Weir  and  Hubert:  Cultures  of  Rusts  107 

developed  uredinia  on  May  30,  followed  by  abundant  telia  on  Jime  3. 

^^  • 

The  remaining  plant  wilted.  Four  control  plants  remained  normal. 
This  cheeks  the  cultures  of  1915.* 

Three  plants  of  CcistiUeja  angustifolia  were  dusted  with  aeciospores  of 
Cronartium  cdeosparoides  (t3rpical  gall  form)  on  Pinus  carUorta  from 
Sylvanite,  Montana,  Jime  23,  1916.  Uredinia  were  not  observed  but  on 
July  17,  1916,  telia  appeared  uniformly  on  all  three  of  the  trial  hosts. 
Three  control  plants  remained  normal.  A  similar  result  was  obtained  on 
Castilleja  with  aeciospores  from  the  gall  type  on  Pinus  contorta  from  Evaro, 
Montana.  Telia  were  recorded  July  17, 1916,  on  orle  of  three  trial-hosts. 
The  remaining  plants  died.    Three  control  plants  remained  normal. 

On  May  23,  1916,  aeciospores  of  Cronartium  coleosporaides  (blister 
type)  on  young  seedlings  of  Pinua  panderosa  from  Haugan,  Montana, 
were  dusted  on  three  plants  of  CaatiU^a  angustifolia.  Heavy  infections 
on  two  and  a  light  infection  on  one  with  xu*edinia  on  June  5  and  teUa  on 
Jime  8  were  recorded.  Three  control  plants  remained  normal.  This 
result  also  checks  similar  cultures  made  in  1915.' 

On  Jime  21,  1916,  aeciospores  of  Cronartium  coleosporoides  (typical 
gall  form)  on  IS-jrears-old  trees  of  Pinus  ponderosa  from  Sylvanite,  Mon- 
tana, were  dusted  on  three  plants  of  Castilleja  angustifolia.  The  ap- 
pearance of  the  uredinia  was  not  recorded  owing  to  absence  from  the 
laboratory  but  on  July  17,  1916,  teUa  were  noted  in  abundance  on  two 
of  the  inoculated  plants.  The  other  trial-host  died.  Three  control 
plants  remained  normal. 

The  results  of  the  season  together  with  those  of  1915  demonstrate 
that  the  various  caulicolous  forms  of  rusts  occurring  on  Pinus  contorta 
and  P.  ponderosa  in  the  Rocky  Mountain  region  are  the  aecial  stage  of 
Cronartium  coleosporoides.  It  is  not  only  possible  but  very  probable 
that  the  same  forms  on  Pinus  contorta  and  P.  ponderosa  as  known  else- 
where in  the  western  United  States  belong  here  also.  An  examination 
of  the  aeciospores  from  galls  on  Pinus  contorta,  P.  ponderosa,  P.  attenuaia, 
P.  couUeri,  and  P.  jeffreyi,  from  widely  separate  regions  has  not  brought 
out  any  specific  characters  different  from  that  of  the  material  used  in  the 
successful  cultures  on  Castilleja.  Attempts  were  made  to  infect  young 
leaves  of  Quercus  rubra  with  aeciospores  from  galls  on  Pinus  contorta  and 
P.  ponderosa  but  without  success. 

Aeciospores  Of  Cronartium  Comptonice  Arth.  on  Pinus  banksiana  from 
Cass  Lake,  Minnesota,  were  sown  on  trial-hosts  as  follows:  On  two  plants 
of  CastiU^a  angustifolia  on  May  17,  1916,  with  negative  results;  on  one 

'  Weir,  J.  R.,  and  Hubert,  E.  E.    A  serious  disease  in  forest  nurseries  caused 
by  Peridermium  filamentosum.    Jour.  Agr.  Research  6:  781-785.    Ja.  24,     1916. 
>  Jour.  Agr.  Research  6:  781-785.    24  Ja.    1916. 


108  Phytopathology  [Vol.  7 

plant  of  Quercua  rubra  on  May  18;  1916,  with  negative  results;  on  one  plant 
of  Comptonia  asplenifolia  on  May  18,  1916,  with  positive  results,  uredinia 
appearing  on  J\me  9  and  teUa  on  June  17.  All  control  plants  remained 
normal. 

Aeciospores  of  Crofiartium  Comptonice  Arth.  on  Pinua  banksiana  from 
East  Tawas,  Michigan,  H-ere  sown  on  trial-hosts  as  follows:  On  three 
plants  of  Castilleja  miniata  on  May  24,  1916,  with  negative  resiilts;  on  one 
plant  of  Qtierciui  rubra  on  May  24,  1916,  with  negative  results;  on  two 
plants  of  Comptonia  asplenifolia  on  May  23,  1916,  and  June  13,  1916,  re- 
spectively. Tredinirf  were  noted  on  June  13  and  telia  on  June  23  on  the 
first  plant  and  unnlinia  on  June  30  on  the  second.  Two  control  plants 
remained  nonnal.  Aociosfwrcs  were  sown  on  one  plant  of  Myrica  earo- 
linensis  and  one  of  Myriai  gale  on  May  26,  1916.  Uredinia  on  Jime  13 
and  telia  on  June*  25  wctc  noted  on  l)oth  plants.  Two  control  plants  re- 
niaincii  nonnal. 

A  collection  of  leaves  of  the  previous  sciu^^m  (1915)  of  Populus  tremu- 
loidcH  lM*aring  telial  sori  of  Mclampsora  rnedusw  Thiini.  vnis  made  in  Pattee 
Canyon  two  miles  .southejist  of  Mi.ssoula,  Montana,  on  March  12,  1916. 
A  p^irtion  of  the^sc*  over-wintered  leaves  were  placed  in  moist  chamliers 
on  March  15, 1916,  and  a  few  days  later  upon  examination  of  the  yellowish* 
brown,  downy  layer  fonne<l  on  the  .*<ori,  it  was  foimd  that  .sporidia  were 
prc»>*c»nt.  Thes<»  fn\sh  siK)ridia  were  ilschI  to  inoculate  newly  formed  nee- 
dles of  lAirix  (Kcid4mUiliH,  Two  separate  inoculations  were  made  on  March 
22.  1916,  followcnl  hy  two  others  on  March  26,  1916.  Individual  branches 
of  trees  of  /..  occidentalis  wv.n*  xh^hI  for  the  test.  On  April  3,  the  first 
inocuLition  had  resulted  in  pycnia  which  w(»re  accompanied  by  small 
droi>s  of  hyalines  licjuid.  On  April  4  the  aecia  were  present  on  the  under 
si<le  of  the  ni^e<llej<.  The  second  in(K*ulation  gave  pycnia  and  aecia  on  April 
4.  the  third  and  fourth  in(H*ulations  re.nulting  in  pycnia  and  aecia  on  April 
8.  Th<»  four  (*ontrol  plant-s  of  L.  occidentalis  as  well  jis  the  needles  on  the 
inoculated  tnM»s  which  wcn»  not  included  within  the  cylinders  remained 
nonnal.  -\ll  the  ikhmIIcs  .subjected  to  the  inoculation  lx?c4une  infected  and 
devclc»j)c<i  a  Lirg'j  niunlx'.r  of  sori  of  l)oth  .st4igi»s  (O  and  I)  of  the  rust. 

On  April  9,  1916,  germinating  t<ilios|K)ric  material  of  Afelampsara 
mt^iumr  Thlim.  on  Populus  tremuloidcs  was  sown  on  two  small  tre<*s  of 
hirij  ruroftea.  On  April  26.  tu\  abundant  <U».velopment  of  pycnia  were 
nHMirded  and  on  May  1  thi^  aecia  ap|H^inid.  The  pycnia'  and  aecia  and 
their  resjK»ctive  sj)ori»-formH  on  the  two  sjiecies  of  larch  were  found  upon 
examination  to  U»  i<lf»ntiral.  The  telial  material  failwl  to  infect  Tsuqq 
hitirophylh  and  Pseudotsutja  taxifitlia,  Tlu»  control  plants  in  all  casesi 
remained  normal. 

TeliosjMires  Uuiring  .s|x>ridia  of  MvUimpsora  mctlusa  Thiim.  on  lea\'cs  of 
Populus  trichocarpa  were  coUf^tetl  at  Haugan,  Montana,  on  June  5,  1916. 


1917]  Weir  and  Hubert:  Cultures  of  Rusts  109 

On  June  7,  these  were  sown  on  one  small  tree  of  Larix  europea,  two  of 
L.  occiderUaliSf  one  each  of  Tsuga  heterophylla,  T,  caroliniana,  and  Pseu- 
dotsuga  taxifolia.  On  June  15,  pycnia  appeared  on  the  needles  of  L.  eu- 
ropea  and  on  the  needles  of  the  two  trees  of  L.  occidentalism  Aecia  developed 
on  L.  europea  in  abimdance  on  June  24  and  on  L.  occidentalis  on  June  22. 
Negative  results  were  secured  on  Tsuga  heterophyUa,  T.  carolinianay  and 
Psexidotsuga  taxifolia.     Control  plants  remained  normal. 

Teliospores  bearing  sporidia  of  Melampsora  bigelomi  Thiim.  on  Salix 
cordata  mackensiana  from  Deborgia,  Montana,  were  sown  on  Larix  occi- 
dentalis and  L.  laricina  on  Jime  7,  1916.  One  small  tree  of  each  species 
was  used.  Pycnia  appeared  on  Jime  15  and  aecia  on  June  18  on  the 
needles  of  L.  occidentalis.  On  L.  laricina,  the  pycnia  were  noted  on  June 
15  and  the  aecia  on  Jime  18.  A  heavy  infection  occurred.  Control 
plants  remained  normal. 

Aeciospores  of  Pucciniastrum  pustulatum  (Pers.)  Diet,  on  Abies  lasio- 
carpa  resulting  from  an  inoculation  with  the  telial  stage  on  Epilobium 
angustifolium*  were  sown  on  two  plants  of  Epilobium  angustifolium  on 
May  18,  1916.  Uredinia  developed  on  Jime  4,  on  the  underside  of  a  ma- 
jority of  the  leaves  subjected  to  the  spores.  Only  the  younger  leaves  be- 
came infected.  Control  plants  remained  normal.  This  completes  the 
cycle  for  Pucciniastrum  pustuiatum. 

TeUospores  of  Gymnosporangium  tvbulatum  Kern  on  Juniperus  scapula- 
rum  from  Missoula,  Montana,  were  sown  on  two  plants  of  Cratcegits 
douglasii  on  April  27, 1916.  Pycnia  in  abundance  appeared  on  May  8  and 
11  and  aecia  on  May  22  and  24.  Control  plants  remained  normal.  This 
checks  a  previous  culture.*^ 

Teliospores  of  Gymnosporangium  nelsoni  Arth.  on  Juniperus  communis 
from  Bonner,  Montana,  were  sown  on  two  plants  of  Amelanchier  alnir 
folia  on  May  21,  1916.  On  June  9,  pycnia  appeared  in  abundance,  the 
aecia  developing  on  June  28.     Control  plants  remained  noVmal. 

Teliospores  of  Gymnosporangium  nelsoni  Arth.  on  Juniperus  scopulo- 
rum  from  Bonner,  Montana,  were  sown  on  two  plants  of  Amelanchier 
alnifolia  on  May  21,  1916.  Pycnia  appeared  on  Jime  6;  aecia  were 
noted  to  be  developing  on  June  28.     Control  plants  remained  normal 

Several  of  the  cultures  are  still  in  progress  of  development  and  as  soon 
as  results  on  these  are  secured  further  information  on  the  rusts  of  forest 
trees  in  this  region  will  be  available. 

Office  of  Investigations  in  Forest  Pathology 
Bureau  of  Plant  Industry 
Missoula,  Montana 

*  Phytopath.  6:  373.    Ag.     1916. 

^  Weir,  J.  R.  Telial  stage  of  Gymnosporangium  tubulatum  on  Juniperus  sco- 
pulonim.    Phytopath.  5: 218.    Ag.    1915. 


A  RHIZOCTONIA   OF  THE  FIG 

J.   Mats 
With  Plate  II  and  Three  Figures  in  the  Text         * 

A  fungiifl  possessing  characteristics  common  to  Rhisoctonia  was  ob- 
8er\T(l  to  occiir  in  the  years  1915  and  1916  on  leaves,  twigs  and  fruit  of 
the  fig,  Ficus  carica,  at  Gainesville,  Florida.  Superficial,  silvery  to  yd* 
lowish  white,  thin  mycelial  strands  of  this  fungus  can  be  seen  to  radiate 
loosely  from  yellow  to  dirty  brown  infection  centers  in  the  fig  leavea  and 
spread  over  the  surrounding  green  tissue.  Later  as  more  of  the 
tissue  becomes  discolored  by  the  invading  mycelium,  the  upper  suifi 
of  these  enlarged  brownish  areas  become  silvery  white  and  dry,  themyogj 
ial  strands  become  less,  if  at  all  visible,  while  the  imder  surfaoes  at  tlie 
corresponding  points  remain  light  brown  to  brown  and  are  uAially  eov^ 
ere<t  with  a  visible  web  of  myceliimi  (fig.  1).  Small,  immature  wbhe, 
as  v»r\\  as  mature  bro^Ti  to  dark  brown  sclerotia  attached  to  mycelial 
threads  are  often  foimd  on  the  petioles  and  midribs  of  infected  leaves, 
but  seldom  are  sclerotia  foimd  on  the  blades  of  such  leaves.  Loosely 
woven,  silky  strands  of  the  myceliimi  of  this  fungus  may  be  traced  to 
some  distance  on  the  twigs.  More  or  less  dense  accumulations  of  sclerotia 
are  usually  grouped  on  one  side  of  the  twig  (plate  II,  fig.  2).  No  direct 
injurious  effect  was  observed  to  have  been  caused  to  the  twigs  by  the 
fimgus.  The  fruit  of  the  fig  may  become  more  or  less  covered  by  the 
spreading  mycelium.  Numerous  sclerotia  are  then  produced  which 
cling  by  mean^  of  mycelial  threads  to  the  fruit  and  its  stalk  (plate  II, 

fig.  1)!* 

Portions  of  diseased  fig  leaves,  and  parts  of  t^igs  upon  which  mycelium 
and  sclen)tia  were  plainly  visible,  were  killed  and  fixed  in  Camoy's  fluid 
and  enilxHlded  in  paraflin.  Cross-sections  of  the  leaf  tissue  reveal  hyphae 
)H*netrating  through  the  ^tomata  into  the  parench>'ma  (plate  II,  fig.  4), 
while  (*ross  and  longitudinal  sections  of  the  twig  tissues  do  not  show  the 
prrM'iice  of  a  |)<.*net rating  mycelium. 

This  fungiLH  was  isolated  from  the  diseased  tissues  of  fig  leaves,  where 
mycelium  but  no  sclen)tia  ^i-ere  present;  and  fnmi  single  sclerotia  taken 
from  twigs.  The  pure  <'ultures  from  lH)th  sources  were  aUke  in  cvcr>' 
n*>|MTt.  I^U"e  cultures  of  this  fungus  wtTt*  grown  easily  for  over  eighteen 
montlis  on  standard  nutrient  agar,  (*orn  nu^al  agar,  and  sterilised  green 


1917]  Matz:  Rhizoctonia  of  Fiq  113 

Of  the  previously  described  specieB  of  BMzootoiiia  the  follcwing  should 
be  considered  here: 

Dr.  Peltier*  in  a  recent  publication  on  parasitic  Rhizoctonias  in  Amer- 
ica summarizes  as  follows:  "At  the  present  time  there  are  recognized  in 
America  two  species  of  truly  parasitic  Rhizoctonias;  the  common  form 
RhieocUmia  Solani  Kilhn  {Corticum  vagum  B.&  C.) ,  widely  distributed  and 
occurring  on  a  great  number  of  hosts;  and  R.  crocorum  (Pers.)  DC, 
with  a  limited  distribution  on  alfalfa  and  potato  tubers.  A  third  Rhizoc- 
tonia, Corticum  ockralettcum  (Noack)  Burt,  is  found  on  the  leaves  of 
pomaceous  fruit  trees,  while  a  fourth  species  isolated  from  damped-off 


^ 


Fia.  3.  Myceuuu  of  Rhieoctonia  HiCBOBCLEaOTiA 
A,  Short  chains  and  a  group  of  short  cells  from  the  margin  of  young  sclerotia. 
X  333.3.    B,  Vegetative  mycelium  from  a  young  agar  culture  on  the  left,  and  from 
ma  old  culture  on  the  right.     X  333.3. 

onion  seedlings  is  of  questionable  parasitism."  In  discuseing  the  growth 
characters  of  a  number  of  strains  of  Rhizoctonia,  Peltier*  makes  the  fol- 
lowing statement  (p.  370)  regarding  the  species  isolated  from  damped-off 
onion  seedlings:  "The  strain  from  onion  produced  sclerotia  which  were 
entirely  different  from  those  of  other  strains  in  that  they  were  small 
(0.5  to  1  millimeter  in  diameter),  perfectly  round,  bright  colored,  and 
developed  submerged  in  the  medium."  None  of  these  latter  characters 
have  been  observed  in  the  Rhizoctonia  from  the  fig.    The  sclerotia  of 

D  America.     Illinois  Agr,  Exp.  Sta. 


114  Phytopathology  (Vol.  7 

this  fim|i^«<  are  roundish  or  oblong,  from  0.2  to  0.5  millimeters  in  diameter, 
an»  not  bright  colored  and  arc  produced  freely  on  the  surface  of  but  not 
in  the  medium  in  culture. 

The  effects  and  manner  of  attack  of  Corticium  ochraleucum  (Noack) 
Burt  on  pomaceous  fruit«,  as  described  by  Stevens  and  Hall,^  are  similar 
to  those  of  the  fig  Rhizoctonia  on  its  host.  However,  the  sclerotia  of  the 
two  fungi  are  entirely  different  and  the  |)erfect  stage  of  the  former  has 
not  so  far  been  found  in  connection  with  the  fig  Rhizoctonia  on  fig  trees. 

I>uggar*  in  his  recent  paper  gives  sufficient  evidence  that  the  conmion 
Rhizoctonia  in  America  is  Rhizoctonia  Solani  Kiihn.  This  Rhizoctonia 
has  Cftrticum  vagum  B.  &  C.  as  its  perfect  stage.  In  comparing  the 
Rhizoctonia  of  the  fig  with  the  Rhizoctonia  Solani  Kiihn,  obtained  fmni 
l)ean  .s<»edlings  here,  the  two  show  pronounced  differences  on  storiliied 
l)ean  plug  and  agar  slant  cultures.  On  each  medium  the  sclerotia  of  the 
first  are  white  at  first,  turning  dark  brown  with  age,  and  remain  small 
and  more  or  less  glolK)se;  the  sclerotia  of  the  second  are  white  at  first, 
turning  light  brown  to  brown  or  dark  brown  and  are  ver>'  irregular  in 
size  and  fonn  (plate  II,  fig.  6).  Mycelium  and  sclerotia  from  pure 
niltunw  of  the  fig  Rhizoctonia  and  from  R.  Solani  Kiihn  were  plac*od  on 
moist  and  growing  fig  leaves  and  twigs.  Both  fimgi  killetl  areas  in  the 
leaf  tissue  but  R.  Solani  did  not  produce  any  scleortia  on  the  infected 
parts.  Two  separate  flats  of  cowpea  seedlings  w<»n»  inoculated  with  the 
two  fungi.  R.  Solani  killed  90  per  cent  of  the  scredlings,  while  the  fig 
fungiL'^  did  not  produce  any  injur>'  to  the  young  plants. 

Shaw*  in  his  account  of  a  Rhizoctonia  which  he  found  on  jute,  nml- 
lK»rry,  cotton,  and  cow])ea,  and  which  he  apparently  misnames  Rhitoc* 
tenia  Solani  Kiihn,  illu.strates  a  fungiLs  which  is  similar  to  the  Rhizoc- 
tonia of  the  fig  in  sevenil  res|x»cts,  i.e.,  the  nonnal  occurn»nce  of  itji 
niuiiennis,  com|>!iratively  small,  rounded  wlerotia  on  the  tips  and  stems  of 
it*<  n»s|KH'tive  host  plants.  However,  the  diameter  of  the  sclerotia  of 
ShawV  Rhizoctonia  is  alnmt  half  of  that  of  the  fig  Rhizoctonia;  the 
color  <»f  the  .*(<!l(Totia  of  the  former  is  black,  while  that  of  the  latter  is 
bn»wn  to  dark  bn>wn.  Shaw's  illustrations  (plat(»  IX)  indicate  a  distinct 
I'ort^^x  in  tin*  srlcrotia  of  his  Rhiz^x'tonia.  which  fonnation  is  al>sent  in 

*  St«'vrnJ«.  F.  L.  ami  II all.  .1.  (I.  HypocnoM*  (if  poinarcHMiK  fniit,  North  Caroltna 
Agr.  Kxp   .^tft.  Hi-p    190e<»:.T.>.  Tft  Ki.  fig?*    II    IV  VMl. 

*  DuKKar.  H.  M.  Uliizoctonia  rroroniiii  (|Vr*4.i  I).  (\  and  It.  Holaai  Kuha 
iCortiriiiiii  vaKurn  H.  tV  ('  <  uith  iiotrM  on  othor  mimm-Icm.     Ann.  MisHouri  Hot.  (lani. 

3:  4o:i-4,>     vm:» 

•.*<haw.  K.  .1  K  MMq»hMloKy  an«i  para«»iti**in  of  Uliizoctonia.  Mc»m.  Dt'pt.  Afpr. 
Iniiia   4:  Ml.     I'.MJ. 

The  (mmiii"  Uhizortonia  in  lii«li:i     Mi*in.  I)i>pt..  Akt..  Iiulia.7:  no.  4.    I9IS. 


1917]  Matz:  Rhizoctonia  op  Fig  115 

those  of  the  fig.    The  mode  of  origin,  as  described  by  Shaw,  of  the  sclero- 
tia  of  the  first,  has  not  been  observed  in  the  fig  fungus. 

In  culture  the  sclerotia  of  the  fig  fungus  develop  from  dense  masses  of 
short  hyphae  and  thefe  the  young  sclerotia  are  usually  s\u*rounded  by 
short  chains  and  groups  of  ovoid,  short,  sometimes  elbowed  cells. 

Zimmerman^  in  describing  Corticum  javanicum  on  Coffea  arabica, 
Coffea  liberica  and  several  other  plants,  mentions  the  occurrence  of  a 
sterile  mycelium  and  small  (0.15  to  0.3  millimeter  in  diameter)  white 
sclerotia-like  bodies  (weisse  Kugelen)  in  association  with  this  Corticum. 
He  states:  "dieselben  treten  sowohl  auf  der  Ober — ^als  auf  der  Unterseite 
der  Zweige  auf  imd  sind  ausserdem  auch  namentlich  haufig  an  den  Friich- 
ten  zu  finden;"  but  no  mention  is  made  of  its  occurrence  on  leaves.  In 
describing  the  effects  of  this  fungus  on  the  host,  Zimmerman  says,  *'Die 
unter  den  Kugelen  gelegenen  Pflanzenteile  sterben — zmn  mindsten  in  den 
nahe  der  oberflache  gelegenen  schichten — ^ab  und  erhalten  eine  dimkel- 
braune  bis  schwarze  Farbung;"  but  no  direct  injiu*ious  effect  from  the 
sclemtia  of  the  fig  fungus  was  observed  on  the  branches  of  its  host.  Re- 
garding the  "Kugelen"  of  Zimmerman's  fungus  he  states:  "vertrocknen 
sie  einfach  an  den  zweigen,  auf  denen  sie  sitzen."  No  mention  is  made 
here  of  the  change  in  color  which  is  a  dark  brown  in  the  sclerotia  of  the 
fig  fungus  at  maturity. 

Edgerton*  described  a  limb  blight  of  the  fig,  due  to  Corticum  Icetum 
Kars.  This  disease  is  characterized  according  to  Edgerton's  illustrations 
nnd  descriptions,  mainly  by  the  conspicuous  fruiting  layer  of  the  fungus 
associated  with  the  diseased  parts  of  the  host,  but  no  mention  is  made  of 
any  Rhizoctonia  occiu-ring  on  fig  trees  afflicted  with  limb  blight. 

Kuijper®  describes  a  leaf  disease  of  Coffea  arabica  and  Coffea  liberica 
under  the  name  of  **Zilverdraadziekte  der  Koffie,"  in  Surinam.  There 
is  a  striking  similarity  in  the  character,  the  manner  of  attack,  and  effects 
of  the  sterile  fungus  which  causes  the  Silverdraad  disease  on  Coffea,  to 
the  Rhizoctonia  of  leaf  blight  of  the  fig.  In  describing  the  Coffea  fungus, 
Kuijper  does  not  mention  nor  illustrate  anything  which  approaches  a 
semblance  of  the  dark  brown  sclerotia  which  are  commonly  foimd  in 
connection  with  the  fig  fungus  on  its  host  and  in  pure  culture.  The 
sclerotia  of  the  latter  are  not  identical  with  Kuijper's  "hyphenkluwens." 
These  forms  occiu*  also  in  his  cultures.  He  states:  '*0p  plaatsen,  waar 
veel,  zijtakken  ontstaan  strengelen  deze  zich  door  elkaar,  zoodat  op  de 

^  Zimmerman,  A.  Ueber  einige  an  Tropischen  Kulturpfianzen  beobachtete 
Pilze  I.    Centbl.  Bact.  Abt.  II,  7:  102.     1901. 

•Edgerton,  C.  W.    Louisiana  Agr.  Exp.  Sta.  Bui.  126:  13,  pi.  VII,  fig.  1.     1911. 

•  Kuijper,  J.  De  Zilverdraad-ziekte  der  Koffie  in  Suriname.  Dpt.  van  den 
Landbouw,  Suriname.    Bui.  28: — 1912. 


116  Phytopathology  (Vol.  7 

Waderen  l)e8rhrevon  khiwens  ontstaan."  In  sonic  of  his  cnlturos  Kuijprr 
obtained  **h>'phon-opconhoopinf2:en  zoo  st<»rk,  dat  bijna  lH)lfomiigi' 
lichaampjos  van  14  2  ni.m.  doorsnedo  ontstaan,  die  l)est{ianuit  oon  l>otrpk- 
kclijk  los  lu^phenvlechtwcrk.'*  Apparently  these  Imdies  never  Uvonie 
in  Knijper's  cultures  a.s  compact  and  colored  as  do  the  sclen)tia  of  the  fig 
fimicus  on  various  media  and  on  the  host. 

Brooks  and  Sharpies''  in  their  work  with  Corticmm  salmonicolor  B.  & 
Br.  (C  jafanicum  Zini)  descrilx*  four  forms  in  which  the  fim^^s  appt^ars 
on  ruhl)er  trees  as  follows:  **a  pink  incrustation  on  the  branches  or  main 
stem;  ....  white  or  pale  pink  ])ustules  arranged  more  or  l<»ss  in 
lines  parallel  with  the  branches;  ....  part  of  the*  fim^s  on  the 
exterior  consists  of  white  or  pale  pink  stnmds  of  a  cobwel)-like  texture, 
which  run  irrei^ilarly  downwards  over  the  surface,  the  strands  l)einK 
.»H)metimes  .<o  <lelicate  as  to  be  overlooked:     ....     finallv  th«»re  is 

the   Necator  stag(* consists  of  oninf?e-n*d   (not  pink)   pu.*^- 

tules  alK)Ut  «)ne-(»ij?hth  inch  in  diameter.'*  In  their  pure  cultures  of  (\ 
salmonicolur,  the  alM)ve  authors  observed  clamp  coimections  in  old  a> 
well  as  young  cultmes,  a  pink  to  a  bright  ros(»  coloration  and,  **aggn'ga- 
tions  of  hy])hae  ....  n^st^nbU'd  a  numlH»r  of  clos<»ly  attached 
Necator  ])ustul<»s."  Practi<*ally  iiorn*  of  thes<'  characters  were  ol>served 
in  the  fig  fungus. 

From  the  precciling  di.*<cu.'<sion  it  follows  then  that  the  Khizoct(»nia 
of  th(j  fig  leaf  blight  is  different  fnnn  all  the  true  s]H»cies  of  Hhizo<*toni.*t 
previously  descrilxMl  and  thus  it  should  Ih»  considcnMl  as  a  new  organism 
which  can  briefly  Ik»  descrilHMl  as  follows: 

Rhizoctonia  microsclerotia  n.  sp. 

Srh-rotia  su]MTlicial.  small  0.2  to  0..')  millimeters  in  diameter,  white 
when  yoimg.  brown  to  dark  brown  at  maturity,  nearly  homogenous  in 
sinK'lure  an<l  color,  sub-glolM>s<',  free  from  t\ift4'd  myi*elium,  not  ."^nHMith 
UMmlly  single,  sometimes  conglomerated. 

Vegetative  hy])hae  0  to  H^i  wide,  first  hyaline  and  granular,  bniwn  an«i 
more  f»r  le**-*  empty  with  m.aturity,  septate. 

Ilab.  On  living  leaves,  branches  antl  fruit  of  tin*  cultivated  fig,  Ficus 
cnrioi,  ( lainesvilk*,  Florida,  V.  S.  .\. 

»•  Hrookii,  F.  r.  an«l  Shan)!**".  A.  Pink  •liHoa.-MV  Dopt.  of  .\Kri.  FcvleratM 
Malav  St!it«'H    Hul    -M  :  1  -27.  fig    1*».     101 1. 


1917]  Matz:  Rhizoctonia  op  Fig  117 

Rhizoctoii^ia  microsclerotia  Sp.  Nov. 

Tuberculis  super ficialibuSy  minusculiSf  0,2  to  0.5  millimeters  in  diameter, 
primum  aUns  deinde  fusco-bruneis  (intus  idem  quod  extus),  similibus 
fere  forma  et  colore  intus  ac  extuSj  sub^lohosis,  floods  myceliaribus  defidenti- 
bus,  non  gUxbris,  saepius  singulatis,  non-nunquam  conglomeratia. 

Hyphis  6-8  li,  latis,  primum  hyalinis  granulosis  deinde  bruneosis, 
septatis. 

Hob.  in  foliis,  ramis  ac  fructibus  vivis  Fid  caricae  cuUae,  Gainesville, 
Florida,  Am,  Bar, 

University  of  Florida  Experiment  Station 
Gainesville,  Florida 


Pl.ATK    II.    KlIlZtM'TONIA    MirKOHC'LKROTiA   ON    FlO 

Vui.  1.  H.  iiiitTusrhTotiii  rovcrinK  ii  tuiic  ami  fruit  of  the  fif(.     X  1.5. 

FiK-  ••  FifC  twiK  defoliHt(*<i  l>y  the  fuiiKUM.  XumorouN  M*lerotia  are  arcumii- 
\iitvi\  on  ono  Hide  of  the  twif^.     X  !..'>.  « 

Ki<i.  3.  Tlir(M'-wiM'kHH>l(l  rultun*^  on  Mtrrilizetl  hotui  {mmIm.  U.  mirrosclerotia  od 
left.  H.  H^ilani  Kiihn  on  right. 

Fi(i.  4.  CroH.H  MOf'tion  of  (liHo;i.'4o<l  fifc  hMif  showinx  prnotration  of  myootium  throuich 
Htomata  at  a  and  h. 

h'ui.  5.  Sf»rtion  throuich  a  Arlcrotiuni  of  K.  mirrosolorotia. 

Via.  Ti.  Srl«*rotia  from  a  Hk  hranrh.     X  2r>. 


11*^ 


1917]  Sherbakoff:  Buckeye  Rot  of  Tomato  121 

any  fungal  growth.  When  the  affected  fruit  is  kept  in  an  enclosure  with 
high  -humidity,  especially  when  the  fruit  approaches  maturity,  the  fungus 
which  causes  the  rot  may  be  observed  commonly  on  its  surface  (fig.  2A). 
The  rot  occurs  on  the  fruit  in  all  stages  of  its  development,  beginning 
almost  invariably  at  the  point  where  the  fruit  touches  the  ground.  Nat- 
urally, the  fruit  touches  the  ground  most  commonly  with  the  blossom-end, 
on  which  account  this  rot  often  appears  as  a  peculiar  form  of  blossom-end 
rot  and  for  which  it  sometimes  has  been  mistaken. 

NAME 

The  disease  is  known  among  some  of  the  growers  on  the  East  Coast  as 
water  logged  fruit.  This  name  cannot  be  adopted  for  the  rot  because  it 
is  misleading  and  because  it  has  no  other  advantage  in  its  use.  The  name 
brown  rot  though  it  would  often  describe  the  disease,  ought  not  be  used  in 
reference  to  the  disease,  first,  because  there  are  even  more  frequent  cases 
when  the  color  of  the  rot  is  not  distinctly  brown,  and  second,  because  the 
name-  has  been  applied  already  by  Bancroft  to  an  apparently  different 
rot  of  tomato  fruit. 

Some  of  the  tomato  buyers  use  the  name  buckeye,  in  reference  to  a  rot 
of  tomato  fruit.  The  writer  was  unsuccessful  in  finding  with  certainty 
what  particular  rot  is  called  by  that  name,  but  his  indirect  information 
and  observations  indicate  that  the  name  refers  to  the  rot  under  consider- 
ation. This  name  describes  very  well  the  most  striking  feature  of  the 
lecaon  on  fruit  affected  with  the  disease,  namely,  its  broad  zonation,  in  which 
case  the  lesion  indeed  much  suggests  the  eye  of  a  large  animal.  The  name 
also  has  not  been  used  in  literature  before  in  reference  to  any  disease  of 
a  similar  natm-e.  Therefore,  it  is  suggested  that  the  common  name,  buck- 
eye, should  be  used  in  reference  to  the  tomato  fruit  rot  described  here. 

OCCURRENCE 

The  rot  was  foxmd  by  the  writer  for  the  first  time  in  January,  1915,  at 
Goulds,  Florida.  Soon  after  the  first  observation  and  during  the  following 
three  months  it  was  found  in  every  tomato  field  of  that  locality  on  the 
prairies — ^low  marl  lands  usually  under  water  during  rainy  summer  months. 
The  whole  district  is  known  as  Redlands  and  lies  at  the  extreme  south 
end  of  the  Florida  East  Coast,  namely,  south  of  Miami. 

The  same  rot  was  observed  by  the  writer  in  1916  on  the  West  Coast 
also.  In  April  of  that  year  it  was  found  in  a  field  near  Bradentown,  and 
in  May  in  a  shipment  of  tomato  fruit  received  by  the  writer  from  a  field 
near  Palmetto.  In  both  instances  the  tomatoes  were  grown  on  the  com- 
mon low  hammock  land  of  that  vicinity. 


122  Phytopathology  (Vol.  7 

The  writer  also  found  amon^  some  old  specimens  of  tomato  fruit  pre- 
><erved  in  fonnaliii  and  kept  in  the  laborator>'  at  Gainesville,  two  ^fieci- 
niens  which  by  external  symptoms  and  microscopic  examination  pnived 
to  Im^  affected  with  this  same  rot.  One  of  the  specimens  had  a  lal)el  indi- 
cating that  it  came  from  Little  River,  near  Miami,  in  1911.  The  other 
8|)ecimen  l)ore  no  label. 

All  these  observations  show  that  the  rot  occurs  in  South  Florida  on 
both  coasts  where  it  is  common  in  low  fields  even  during  a  comparatively 
dr>'  season,  such  as  that  of  1916.  No  actiail  observations  were  made  of 
its  occurrence  in  other  parts  of  the  state,  but  judging  from  its  common 
presence  in  so  widely  separated  parts  as  the  east  and  west  coasts  and  on 
soils  s<j  different  in  character,  one  might  safely  assume  that  it  is  much  more 
generally  distributcnl  than  observations  indicate. 

HISTORY 

The  ])rescTvr(i  s|>(»ciin<»n  of  the  rot  found  in  the  lal)orator>'  and  previ- 
<)iL*<ly  mentioned,  shows  that  the  (lis<*as(»  was  pres<Mit  in  the  state  at  least  a^ 
early  as  1911.  An  incpiiry  among  tomato  growers  of  the  East  Coast  aL«o 
indicates  that  it  hjis  existed  ther(^  a  long  time. 

Pathological  literature,  with  one  excerption,  contains  no  reference  to  any 
dis<»as(»  of  tomato  fniit  similar  to  the  rot  \mder  consideration  here.  The 
organism  which  caus<»s  this  rot  is  clos(»ly  related  to  I^hytophthora  infe^ftarut 
but  the  latter  fung\is  is  not  the  same  as  the  one  which  causes  the  rot  herein 
de.**crilxjd  and  the  disease*  prochiced  by  I\  infcstans  is  also  dilTf»rent  lie- 
cause  it  affects  all  aerial  parts  of  th(^  plant  and  the  fungus  always  pnNlu(^*> 
abuiulant  conidia  on  the  surface  of  the  afT(Tted  parts  of  the  fruit. 

The  previously  mentioned  exception  is  a  short  note  by  Bancroft*  on  llio 
Brown  Rot  of  the  Tomato,  in  which  is  descrilKMl  briefly  the  s>'mptoms. 
orcurreiice,  economic  im|N)rtance,  and  the  method  of  transmission  of  the 
dis<»a.*«4*.  No  illustrations  of  any  kin<l  at'company  the  article  to  assist  in 
identifi<*ation  of  X\\v  dis4*a.*<<»  and  in  general  it  is  t<K)  brief  to  judge  with 
rerlainty  whether  tlu*  tomato  fruit  rot  n'|H)rted  from  Knglan<l  is  the  same 
as.  or  difTen*nt  from  the  rot  found  in  Florida.  It  apjX'ars  tlmt  the  rot  of 
tomato  fniit  re]>orted  by  Banrroft  has  thc»s4'  two  ft^itures  similar  to  the 
burkeye  rot :  « 1 )  The  dis<»as<*  occurs  «)nly  on  the  fruit ;  (2)  the  fungus  asscK 
ciateil  with  tin*  rot  in  Kngl.ind  is  closiHy  related  io  the  fimgus  which 
cttUS4»s  the  r«»t  in  Florida.- 

*  Hanrrnft,  C.  K.  The  Immn  nit  ni  toninto.  Jour.  M.  .\in'.  (London)  1$:  1012. 
1910 

»  Whether  It  i*  ri'.illy  thr  simw  fiiiiKU«t  or  ii«»t  it  is*  iiiipoMiMc  to  determine,  be- 
rnuM*  ulioitt  III**  fuiiKa?^.  Daiicroft  iiicrrly  nay^  "the  tiHMiieit  of  the  endosperm  and 
emhryo"  nf  thr  afTrrte*!  need  "contain  fungal  hyphae,  which  from  their  cbarmclert 


1917]  Sherbakoff:  Buckeye  Rot  of  Tomato  123 

The  points  in  which  the  two  rots  appear  to  differ  are  as  follows:  (1)  In 
describing  the  rot  in  England,  Bancroft  says:  "A  fruit  which  is  infected 
first  shows  discolored  patches  on  its  surface;  these  usually  run  together, 
so  that  the  whole  or  almost  the  whole  surface  of  the  fruit  becomes  discol- 
ored." The  rot  observed  in  Florida  as  a  rule  appears  in  form  of  one, 
rarely  more,  gradually  spreading,  often  distinctly  zonate  spot,  usually  at  the 
blossom  end  of  the  fruit;  (2)  Bancroft  from  all  his  observations  on  the  rot 
says  this  in  regard  to  the  way  in  which  the  disease  affects  the  fruit:  "This 
infected  seed  ....  is  known  among  the  growers  to  be  capable  of 
germinating  and  is  reported  to  produce  plants  which  always  bear  infected 
fruits.  These  facts,  coupled  with  the  results  of  microscopic  examination 
of  the  seed,  suggest  that  the  hyphae  may  be  capable  of  existing  in  the  seed 
in  a  resting  condition,  becoming  active  when  the  seed  germinates,  and  keep- 
ing pace  with  the  growth  of  the  plant  until  the  fruit  is  formed."  That 
is,  Bancroft  evidently  records  no  other  method  of  infection  of  the  fruit 
than  the  one  suggested  in  the  above  citation,  while  it  is  evident  that  in 
the  case  of  the  rot  in  Florida  the  infection  starts  from  outside  the  fruit. 
From  the  above  citation  it  is  also  evident  that  the  rot  reported  by  Ban- 
croft is  associated  rather  with  the  use  of  infected  seed  (the  plants  from  in- 
fected seed  "always  bear  infected  fruits")  while  in  our  case  it  evidently 
is  associated  with  the  infested  soil,  and  only  the  fruits  which  touch  or 
nearly  touch  the  ground  are  affected  with  the  rot. 

On  the  whole,  it  seems  that  the  disease  described  by  Bancroft  is  differ- 
ent from  the  rot  of  tomato  fruit  found  in  Florida,  and  the  latter  should 
therefore  be  considered  as  a  new  one  to  the  literature. 

ECONOMIC  IMPORTANCE 

The  data  at  hand  will  not  justify  any  precise  statement  concerning  the 
extent  of  damage  caused  by  the  rot.  But  considwing  that  the  tomato 
crop  is  the  most  important  of  all  vegetable  crops  in  Florida,  and  consider- 
ing also,  that  the  rot  was  actually  observed  to  affect  up  to  fifteen  per  cent 
of  the  fruit  in  the  field  and  up  to  ten  per  cent  of  the  fruit  in-transit,  it  is 
evident  that  the  disease  is  important. 

CAUSE 

Repeated  isolations  from  the  tissues  of  tomato  fruit  affected  with  the  rot 
invariably  yielded  one  and  the  same  fungus,  usually  in  pure  cultures  di- 

appear  to  be  hyphae  of  Phytophihora  omnivora.^*  Hyphae  of  a  number  of  fungi 
belonging  to  the  same  family  do  appear  under  similar  conditions  alike,  the  fungus 
causing  the  rot  in  Florida  included;  and  yet  they  are  quite  different,  but  to  differ- 
entiate them  much  more  than  appearance  of  the  hyphae  is  needed. 


124  Phytopathology  [Vol.  7 

rectly  fn«n  plantings.  The  firbt  isolations  were  made  from  the  material 
collectoil  on  the  Kast  Coast,  in  Janiiar>%  1915;  the  last  in  May,  1916,  from 
material  obtained  fnnn  the  West  Coast. 

The  isolations  wvre  made  hy  planting  small  bits  of  the  affe<*ted  tissin*:* 
(from  under  the  epidennis  and  after  the  fruit  was  disinferted  in  menMirir 
ehloride  sohition,  1  :  KNM),  for  aUnit  fifteen  minutes)  into  either  {X'tri 
dishes  with  a  suitable  mediinn  (<*orn-nieal  and  oat  agars  wen*  most  com- 
numly  used  for  this  pur]K»se)  or  into  test-tulH»s  with  sterilized  lioan  |>o<l< 
or  oat  agar.  Dilutions  of  swarm-si>ores  wen'  <Mnploved  to  make  certain 
that  the  cultures  were  pure.  This  was  an  «»asy  proci»dure  l)ecauw  the  fun- 
gus readily  s]><»rulat(»s  and  the  swarin-s|>ores  an*  produced  from  mature 
conidia  ^swannsporangia)  in  a  very  short  time  and  practically  under  all 
conditions  of  th<*  lalNuatory  (under  favorable  <u)nditions  s^'ann^pores 
were  (>roduced  in  some  instances  eight  minutes  after  the  culture  was  plaoed 
in  frrsh  water).  \  very  successful  proc(Mhire  here  is  t<»  place  a  ffood- 
sized  pitM'c  of  )M'an-|)o<l  (*ulture  (two  or  nion*  weeks  ol<|)  of  the  fuilglM 
into  a  sterilize* I  watch-glass,  with  a  frw  <'ubic  rciitimet«Ts  <if  Hterilind 
water  in  it.  for  al>out  fortVH'ight  hours;  then,  after  the  culture  in  thtt 
watrh-glass  is  washed  a  few  timrs  in  fresh  striilizrd  wat<T,  it  is  left  in  the 
watrh-glas?*  with  a  frw  cubir  crntinu'trrs  of  wat«T  for  half  an  hour.  In 
the  first  two  days  the  lM*aii-p<»d  cultun*  usually  produces  a  great  masB  of 
ronidia;  in  half  an  hour  or  an  hour  after  it  is  rinsed,  these  im'annspcrBngMl 
will  liU*rati'  int(»  tht>  water  a  ronsidcpablr  number  of  swarm-spores;  this 
water  with  numerou'^  >warni-**|)ores  in  it  '\<  to  be  us«m|  then  for  poured* 
]>late  dilutions  made  in  the  ordinary  way.  ( *orn-meal  agar  was  com- 
monlv  :ind  >uiTes««ful!v  umm|  I»v  the  writer  for  these  dilutions. 

•  •  • 

Inortilution**  of  tomato  fruit.  detarh<>d  from  the  f)laiit,  and  not  detached, 
anil  of  all  •'tani's  from  very  yoinm  to  n'd.i'i(M'  with  ])ure  cultures  of  the 
fungu**.  inv.'triably  n*>ulted  in  re])rodurtion  of  the  rot  (fig.  2).  The  inocu* 
lalion-i  wen*  made  by  plaeing  sm.all  bit<  of  the  culture  and  water  Hiu^pen- 
^•ion*'  of  *warm-^pores  upnn  wounded  and  un wounded  "Surfaces  of  the  fruit. 
In  the  (';i*«e  of  '*w:inii-^]MiM-  iiiiH  u]:ii ii»ii  a  pjerr  of  th«'  fungus  culture  wa.s 
dri»]»[H-d  intii  a  l.iii:«'  j.ii  nearly  full  nf  -lerilizid  w.ati-r  and  then  the  fruit 
wa*i  pla<-<'d  mtii  thr  watii.  Deiarlu'd  liiMiato  fruit-*  float  in  water  and  un- 
iletaj'heij  fruit  ran  Im-  eniiVi-nii'iil Iv  ]jla«-ed  in  '•ueh  :i  way  that  only  a  part 
of  It  vill  bi-  in  till-  water. 

huM'ulatinns  iiitii  wmmdeij  funr  ne.trly  :ih\;iy-  -liowed  the  rot  in  tWt»nty- 
four  hour-.  Iiiorulatmn-  iiiti»  unwounrjrd  fiuif.  wliethiT  myrclimn  or 
-Warm— |H>rf-  wiir  rni]»l«»\i  li.  •^nmrinnr*.  ohn\M-d  the  rot  in  lwi»nty-four 
hour-  .ifier  thr  iri«»iu!:iMf»fi  \\a-  maiji".  but  oftrn  the  inferiion  c<»uld  not 
III-  ijfTi  itril  until  thn-r  t»i  •vi-n  four  ♦lay-  later.  \\  ]»ii*s**nt  no  explana- 
tii»n  1-  f»lT'ri'.|  for  t*'is  variatM»n  mi  the  ineubalion  |M'riod. 


126  Phytopathology  (Vol.  7 

Th<»  fungiis  has  Ikvii  j^rown  and  studiiMl  on  various  niotlia  parallel  with 
other  organisms  related  to  it,  sueh  as  Pythium  debaryanum  He««*.,  Py- 
thiacystis  ciirophihcrn  Sin.  &,  Sm.,  and  s<»veral  s|)eoies  of  Phytophthora, 
P.  cnctorum  (I>»lKTt  &  Cohn)  Sehr.  and  P,  er y throne ptica  Pethybr.  in- 
rhided.  Tliis  eoniparative  study  shows  plainly  that  the  fungus  causing 
till*  huekeye  rot  of  tomato  fruit  is  different  from  tlM»  others.  Its  peculiar 
tufte<l  gn»wth  on  the  corn-meal  agai*^  in  plates,  is  one*  of  the  differentiating 
characters,  <»s|KM*ially  valuable*  for  an  easy  s<»paration  of  this  fungus  fnmi 
the  others  (fig.  3). 

Kxamination  of  the  literature  also  indicates  that  this  fungus  luis  no 
U»en  ])reviously  di'scrilMMJ.  However,  evidently  th<'  same  organism  wa 
isolated  iH'fore.  though  from  another  host;  but  it  has  Ikvii  considere<i  to 
Im^  the  siune  as  the  fungus  of  the  lemon  brown  rot,  namely,  Pythiacysth 
nirnphthorn  Sm.  A:  Sm.  The  ref<»renee  hen*  is  made  to  the  organism  iso- 
lated by  II.  S.  Kawcett^  an<l  by  11.  K.  St<  vens  from  the  bark  of  citnis 
ln»es  in  Flori<la  affected  with  the  foot  rot. 

The  writer's  C4)mparativ<»  study  of  the  fungus  of  the  buckeye  n»t  of 
tomato,  of  the  fungus  of  the  lemon  brown  rot.  P.  citrophihoro,iind  o{  the 
fungus  from  \\\v  citrous  f(M>t  rot  in  Florida  shows  that  the  tomato  n>t 
organism  ami  the  one  of  the  citrous  foot  rot  are  morphologically  aiul cultur- 
ally identical  and  that  it  is  <listinctly  different  f nun  the  true /^  ri7ro/>/i//ifwci. 

.V  fungus  was  recently  isolatcvl  by  the  writer  from  a  lupine  stem  n>t 
which  IS  evidently  the  sam<'  as  the  one  of  the  buckeye  rot  of  tomato  fniit. 

liHM'ulations  of  tomato,  sw<H't  |M'p|M'r.  watermelon  fruit,  of  lemons  and 
of  iuIhts  of  Irish  |>otat<H's  with  pure  cultures  of  the  s<'veral  s|K»cies  of 
Phvtophthora,  ])reviou>lv  mentioned,  of  the  Pvthium,  IMhiacvsti**  and 
thn*^'  strains  of  the  fungus  of  the  buck(\ve  rot,  inclu<ling  one  strain  isolated 
by  H.  K.  Stevens  from  <lis<»as4M|  bark  of  a  citrus  tre<'  in  Florida  affected 
with  the  f(H)t  rot,  sh<»w  that  certain  organisms  distinctly  diffen»nt  in  their 
mor()hology  may  affect  the  same  host  and  pnxluce  more  or  lc*ss  similar 
effects.  The  fungus  of  the  Inickeyt*  rot  prcMhu'cd  a  rot  of  all  the  parts  of 
the  plants  hen*  n'ftTnMl  to. 

These  inoculations  thus  indicate  that  the  organisms  which  do  attack  the 
Sjiiiie  plant  or  ]>lants  cannot  on  this  basis  alone  )><*  considen*d  identical 
with  each  <»ther. 

•  Thi*  t<»rri-fiH*al  »ic»r  i?*  inudr  l>y  hratiii)!  .'lO  teraiiiM  of  r<>rii-int>nl  in  inOU  rr.  of  Ui*- 
ttllfil  wnt4'r  at  fio  ('.  for  an  hour,  then  filtrriiiK  tli«'  li(|ui(l  through  i\  filter  paper, 
adWiiiK  to  It  \'»  itrninn  of  agar  and  the  rfciuiml  amount  of  <iiHtill(Hl  wat(*r  to  KrinK 
vohinu'  of  thr  h<|tii<l  to  KWM)  rr..  ('(Hiking  the  Muh?«t:uire  in  a  doiihlr  lK>ilcr  until  ml! 
agar  in  (li!*S4»lv('4l.  ((Mihng  <ioun  to  .V)  i\.  .vhhng  the  white  of  an  egg.  nutoelaviii|t 
at  l.'*  |KMin(l»  of  preHxure  for  alnMit  fifteen  iiiinute»<,  filtering  through  a  filter  pa|M*r. 
tiihing  and  auto*  laving  a*  Ix^fore 

•  Fa^eetl.  II.  S.  Tho  known  (lixtriluition  of  I*vthiae\>ti?«  citniphthora  an«l  it» 
pfohahlc  relati(»n  to  mal  di  goninia  of  rit^l^.     IMiytopath.  6:  tWK  07.     1915. 


1917]  Shebbakoff:  Buckeye  Rot  op  Tomato  127 

On  the  basis  of  the  data  obtained  in  the  course  of  the  writer's  compara- 
tive study  of  the  fungus  of  the  rot  of  tomato  fruit  and  of  the  other  fimgi 
related  to  it,  it  is  considered  an  undescribed  species  which  may  be  briefly 
characterized  as  follows: 

Phytophthora  terrestria  n.  sp. 

Myceliiun  at  first  continuous  then  septate;  conidia  usually  terminal, 
sometimes  intercalary,  mostly  oval,  papillate  at  apex  but  variable,  42.5 
X  30.5  (36-46  X  24-35)|i|  germinating  mostly  by  swarm-spores;  swarm- 
spores  asymmetric,  with  two  cilia  on  one  side,  9.5  (&-ll)|i,  when  in  resting, 
globoid  stage;  chlamydospores  common,  mostly  globose,  34  (SO-40) /jl;  oogo- 
nia  common  in  old  cultures  on  steamed  bean  pods,  globose,  22  (19-24)|i 
with  the  stalk  evidently  penetrating  through  large,  nearly  globose  antheri- 
dium  (fig.  4);  oospores  globose,  20  (18-21)^;  colonies  on  corn-meal  agar,  in 
petri  dish,  peculiarly  tufted. 

Hab.  Parasitic  in  tomato  fruit  causing  buckeye  rot,  in  bark  of  trunks 
of  citrus  trees  causing  foot  rot,  in  stems  of  a  Lupine  causing  stem  rot,  and 
apparently  in  low  soils;  in  Florida. 

Phytophthora  terrestria  sp.  nov. 

Mycelio  priuo  continuo  deinde  septato;  conidiis  fere  terminaltbus  aliquando 
ifUercalaribiia,  pterumque  ovoideis  apice  papiUatis  sed  vcUde  variabUibua, 
4£'5  X  S0.5  {36-46  X  24-35)yL,  per  zoosporos  fere  germinatis;  zooaporis 
aeymmetris,  laieraliter  S-ciliatis,  9.6  {9-ll)yL  diam.  quum  quieti,  globosi  statu; 
chlamydosporia  vtUgarilms,  plerumque  gkbostbtAa,  34  (30-40) fi  diam.;  ooganiis 
globosis,  22  {19-24) ii  diam.,  radicibua  per  amplum  sub-globosum  antheridium 
aperte  penetrantibus;  aosporis  globosibus  20  {18-21)ii  diam.;  cohmiis  in  agaro 
Zeae  Maydis  farina,  in  petri  patera,  euo  genere  criakUi. 

Hab.  paraaitice  in  frudibue  Lycopercici  esculenti  efficiens  "bitckeye  rot,** 
in  tmcis  Citri  efficiens  ''foot  rot,"  in  caulibiLS  Lupini  sp.  efficiens  **stem  rot," 
et  aperte  in  humiUbus  solis,  Floridensibus,  Am.  bar. 

CONTROL 

No  direct  control  experiments  with  the  buckeye  rot  have  been  con- 
ducted, but  the  fact  that  the  rot  occiu's  almost  invariably  only  when  the 
fruit  touches  the  ground,  or  is  very  close  to  it,  naturally  suggests  staking 
the  tomato  plants  to  prevent  it.  The  staking  would  hold  the  fruit  high 
enough  above  the  ground  to  keep  it  from  attack  by  the  fimgus. 

The  fact  that  the  fungus  attacks  the  fruit  from  the  groimd,  coupled 
with  the  fact  that  the  rot,  once  it  starts,  progresses  under  normal  condi- 
tions fairly  rapidly  (often  nearly  the  entire  fruit  may  become  affected  in 


Phytopathologt  {Vol.  7 


1917]  Sherbakopf:  Buckeye  Rot  op  Tomato  129 

three  days  after  inoculation,  the  rate  depending  evidently  on  the  tempera- 
ture, moisture  content,  and  maturity  of  the  fruit),  also  suggests  a  method 
of  control  of  the  rot  while  in  transit.  Here  it  probably  would  be  very  ad- 
vantageous to  keep  the  fruit  for  a  few  days  after  it  is  picked  before  pack- 
ing it  for  shipment.  All  fruits  that  were  infected  in  the  field  would  de- 
velop the  rot  sufficiently  to  be  detected  by  the  packers  and  thus  be  thrown 
out  without  contaminating  the  rest  of  the  fruit,  which  then  could  be 
safely  packed  and  shipped.  But  the  practicability  of  these  methods  has 
not  been  tested. 

SUMMARY 

1.  The  buckeye  rot  of.  tomato  fruit  is  common  in  certain  places  on  the 
low  lands  of  the  east  and  west  coasts  of  Florida. 

2.  It  occurs  only  on  the  fruit  that  touches  or  nearly  touches  the  groimd. 

3.  It  is  caused  by  the  fungus  Phytophthora  terrestria  n.  sp.,  which  is  also 
found  on  other  hosts. 

4  It  causes  considerable  injury  to  the  fruit  in  the  field  and  in  transit. 

5.  Staking  of  the  plants  in  the  field  and  keeping  over  the  picked  fruit 

a  few  days  before  it  is  packed  seem  to  be  practical  methods  of  its  control. 

UNrvERsiTY  OP  FLORroA  Agricultural  Experiment  Station 
Gainesville,  Florka 


Explanation  op  Fig.  5 

Af  conidiophores  from  culture  on  hard,  oat  agar,  eight  days  old.  X  100.  B, 
conidiophores  and  C,  intercalary  conidia;  from  the  same  medium  and  of  the  same  age 
as  A,  D,  conidiophores  from  the  fimgous  growth  on  an  artificially  inoculated  (up- 
per) and  on  naturally  (lower)  affected  and  nearly  mature  tomato  fruit.  Ej  oospores 
within  the  oogonia  with  the  basal  antheridia  evidently  penetrated  by  oogonial 
stalk.  Ff  germinated  chlamydospores.  G,  t3rpical  and  H,  various  abnormal  forms 
of  conidia,  produced  on  surface  of  a  mature  tomato  fruit  affected  with  the  buckeye 
rot.  I,  resting  and  germinating  swarm-spores.  Ky  motile  swarm-spores  (fixed  in 
Flemming's  fluid  and  stained  with  eosin).  L,  conidium  germinating  by  a  single 
germ  tube.  M,  two  conidia  germinating  by  many  germ  tubes  (evidently  each 
swarm -spore  which  did  not  escape  gives  its  own  germ  tube).    B-L  X  500. 


NOTEWORTHY  PORTO  RICAN  PLANT  DISEASES 

F.    L .    Stevens 

The  following  diseases  are  of  interest  to  pathologists  of  the  United 
States,  either  because  they  are  new,  or  because  they  are  little  known 
diseases  of  important  crops  belonging  within  the  territory  of  the  United 
States  or  are  caused  by  fimgi  of  special  interest  for  one  reason  or  another. 

CoFFEB.  Pellicvlaria  koleroga.  This  fungus  occurs  in  great  abun- 
dance, especially  in  the  lower  altitudes  in  Porto  Rico.  In  destructiveness 
and  general  appearance  it  gives  an  impression  somewhat  like  that  of  pear 
blight  with  many  branches  killed  and  the  dead  leaves  matted  and  hang- 
ing by  their  fungous  attachments.  The  fungus  forms  thin  skin-like 
membranes  over  the  lower  leaf  surfaces  and  has  thread-like  growths 
leading  down  the  petiole  and  adjacent  branches.  In  habit  it  strongly 
resembles  Hypochnua  ochrohucua  Noack  as  it  occiu*s  on  apples  in  the 
Carolina  mountains,  and  the  writer  long  has  had  the  suspicion  that  the 
two  fungi  are  related. 

Hemileia  vdstatrix.  This  destructive  fungus,  though  not  seen  in  Porto 
Rico,  is  worthy  of  mention  on  that  account.  There  is  a  report  that  it 
was  imported  into  the  island,  almost  immediately  recognized,  and  due 
to  the  vigilance  of  th^  experiment  station  officials  was  so  thoroughly 
eradicated  that  not  a  specimen  has  since  been  collected.  The  following 
quotation  from  a  letter  from  Mr.  May,  in  charge  of  the  Porto  Rican 
Experiment  Station,  is  worthy  of  record. 

"When  the  station  was  first  established  in  Porto  Rico  we  were  carry- 
ing on  some  experiments  in  the  Carmelita  cofifee  plantation,  five  hours  by 
horseback  above  Ponce,  imder  charge  of  J.  W.  Van  LeenhoiBF.  In  19(^ 
or  1903,  I  do  not  remember  which,  it  was  before  I  came  to  the  station, 
Van  Leenhoff  got  some  little  coffee  trees  from  a  Dutch  warship  that 
brought  them  from  Java.  After  he  planted  them  out  he  noticed  that 
they  had  what  appeared  to  be  Hemileia  vcistatrix.  Mr.  Van  Leenhoff 
had  been  a  coffee  planter  in  Java  and  was  pretty  sure  of  the  fungus  from 
such  investigation  as  he  could  make.  The  matter  was  commimicated  to 
Washington  and  L.  A.  Clinton,  of  Connecticut,  was  sent  down  to  inves- 
tigate the  trouble.  In  the  meantime  Van  Leenhoff  took  every  precau- 
tion, destro3dng  all  the  plants  and  all  material  that  might  have  in  any 
way  been  connected  with  them.    Clinton  spent  some  weeks  at  the  Car- 


1917J  STBVBNS:  PORTO   RICAN   PLANT  DISEASES  131 

melita  but  oould  find  no  traces  of  the  fungus  and  as  none  has  appeared 
since,  Van  Leenho£f  doubtless  made  a  'dean  up.'  Since  that  time  great 
care  has  been  exercised  with  all  coffees  brought  from  foreign  ooimtries." 

StUbeUa  flavida.  The  characteristic  circular  leaf  spot  caused  by  this 
fungus  is  common  in  the  higher  altitudes,  but  is  never  fo\md  in  low  re- 
gions. The  fungus  is  of  imusual  scientific  interest  on  account  of  its 
problematic  relationships.  It  is  by  no  means  limited  to  coffee  but  is 
found  on  numerous  hosts. 

Sugar  Cane.  Lepiosphceria  Sacchari,  This  fimgus  is  quite  commonly 
present  as  a  destructive  leaf  spot. 

Palm.  Graphida  Phoenicis.  This  fimgus,  which  is  of  uncertain  re- 
lationship and  is  common  as  a  minor  pest  in  northern  greenhouses,  is 
found  in  the  open  on  several  species  of  palms  in  Porto  Rico.  It  has  been 
noted  particularly  upon  the  date  palm  and  the  hat  palm.  The  hat  pahn 
is  a  very  profitable  plant,  a  single  leaf  being  worth  about  ten  cents.  Fre- 
quently trees  arc  seen  with  all  the  leaves  closely  covered  with  Graphiola 
and  lines  of  diseased  tissue  reaching  long  distances  through  the  petioles. 
The  financial  damage  is  done  to  the  young,  as  yet  imfolded  leaves,  the 
fungus  penetrating  them  and  rendering  them  worthless. 

Melicia  furcaia.  This  is  present  sometimes  to  such  extent  as  to  largely 
cover  the  leaves  with  its  black  coating.  It  has  not  been  observed  on  cul- 
tivated palms  but  occurs  in  great  abundance  on  wild  Thrinax  ponceana 
on  plants  of  marketable  size.  As  yet,  however,  there  seems  to  have 
bepji  no  attempt  to  make  a  commercial  enterprise  of  shipping  the  bcau- 
tifiil  young  palms  which  spring  up  spontaneously  in  such  profusion  in 
Porto  Rico. 

Auer$waldia  palmicola.  This  was  noted  only  a  few  times,  but  in  those 
instances  affected  nearly  evcr>'  leaf  and  leaf-segment  on  the  tree. 

Bread  Fruit.  Oredo  Artocarpi,  The  inmiense  leaves  of  the  bread- 
fruit harbor  numennis  fungi.  The  crop,  if  it  can  l)c  called  such,  is  not 
of  high  value,  and  this  r\tst,  though  interesting,  is  not  of  much  economic 
signific4ince. 

Corn.  PhyUachora  graminis.  Mention  liaj<  Iwen  ina<le  of  this  in 
Phytopathology  by  Miss  Nora  Dalby.  The  disease  was  \%nde-spread  in 
Porto  Rico  and  must  Irnve  l)een  to  considtTuble  exti»nt  injurious. 

Bean.  I>imerium  grammodes.  This  striking  fungus  which  occupies 
and  covers  the  veins  of  the  affected  jmrts  of  the  leaf  with  i\^  conspicuous 
black  perithecia  is  common  on  several  grnera  of  h^gtuncs,  among  them 
cultivate<i  beans. 

GuAVA.  Meliola  Pauiii.  The  Mark  s|>ots  of  this  fungiu<  an»  almost 
universally  pn»sent  where\Tr  the  host  is  foimtl.  Then*  is  but  liitli*.  if 
any  injiuy. 


132  PHYTOPATHOLOGY  [VOL.   7 

Aschersonia,  What  is  taken  to  be  one  of  this  genus  sometimes  occurs 
profusely  on  the  lower  surfaces  of  guava  leaves,  giving  them  a  livid  scar- 
let color,  conspicuous  to  a  considerable  distance.  The  fimgus  appears 
to  be  growing  upon  a  scale  insect,  probably  Alerodes  citri. 

Cephaleurus  tnrescens.  This  algal  parasite  is  of  special  interest.  The 
spots  show  well  from  both  below  and  above  the  leaf,  the  leaf  tissue  being 
killed.  This  alga,  also  widely  known  as  the  cause  of  a  serious  tea  dis- 
ease, is  present  parasitically  on  a  large  numl)er  of  Porto  Rican  plants. 

GoNDULE.  Uromyces  dolicholi.  This  universally  present  leguminous 
plant  is  almost  always  rusted  to  a  slight  degree,  sometimes  badly  rusted. 

Mango.  Meliola  Mangiferce,  Meliola  is  very  common  and  wide- 
spread but  apparently  not  injurious.  Gloeosporium  mangiferct  is  often 
abundant  and  injurioiu^,  especially  upon  the  fruits  of  the  finer  varieties 
of  the  mango.  The  effect  in  general  is  much  like  that  of  the  bitter  rot 
on  apple. 

Sweet  Potato.  Coleosporium  Ipomcece,  Rust  is  common  on  this  and 
other  Ipomoeas,  but  iLsually  not  t^)  serious  extent.  In  one  field  at  Pres- 
ton's Ranche  near  Nagualxi,  infection  was  general  and  serious.  Each 
sorus  was  also  parasitized  by  a  Fusarium-like  fimgus,  rendering  it  white. 

Grape.  Physopella  vitis.  This  is  a  rust  of  cultivated  grape.  Three 
collections  were  made  in  Porto  Rico  but  all  from  the  same  vines,  namely, 
at  Patillo  Springs.  The  rust  was  pn»,sent  in  quantity  suflScient  to  make 
it  injurious.  The  writer  knows  of  only  a  few  grape  vines  in  Porto  Rico. 
If  there  were  more  \'\nv»  perhaps  there  would  have  been  more  collec- 
tions of  this  rust. 

Peantt.  Vramyces  arachidis.  Only  one  collection  of  this  rust  was 
made.     Indec^d,  the  peanut  plant  is  not  very  common  in  Porto  Rico. 

Canxa.  Pxicciniii  Canruz.  The  rust  on  Canna  is  common  on  both 
wide  and  cultivated  Cannas  in  all  parts  of  Porto  Rico;  on  nearly  evcr\' 
one  of  the  host  plants.  Sometimes  the  rust  is  so  abundant  as  to  appear 
fairly  destructive. 

I. NO  A  Lai'rina.  Microstroma  sp.  This  host,  an  important  leguminous 
coffee  shade  tn»e,  is  frec|uently  nmrh  infej^ted  ^^ith  an  undescribed  Micro- 
stroma  which  ca\L**es  large  witches  br(M>ms. 

Pitiiecolobium  Saman.  MicroHtrama  sp.  This  le^(uminous  tree  is 
being  intro<hic<Hi  into  Porto  Rico  through  the  (efforts  of  the  experiment 
station,  and  in  the  sihmI  Ih»(L<  and  propagating  lyoiU  it  is  frequently  heavily 
infest4Ml  with  an  ap|wrc»Jitly  un<le-»<cril>ed  sp<H*ies  of  Microstroma. 

Pasi»alum.  MyriftgctutsfHtra  .**]).  Th(»  Pa.»*pahmis  of  yard  and  pa*- 
tUH'  <ift4*n  lH»ar  this  vcr>-  intc»n»sting  fungiu*.  Infertion  is  usually  gen- 
eral throughout  thr  plant,  that  is,  if  one  part  is  infected  e^ich  leaf  is  likely 
to  Ik*  invad(*d. 


1917]  STEVENS:   PORTO   RICAN   PLANT  DISEASES  133 

Melia.  Psendoperonospora  sp.  Two  collections  were  made,  in 
widely  separated  parts  of  the  island,  of  this  fungus.  The  damage  is 
probably  slight.  The  four  fungi  last  mentioned  will  be  described  fully 
by  Dr.  Lamkey. 

Ficus.  Kuehneola  Fid,  This  rust  was  very  conspicuous  and  pres- 
ent on  a  large  number  of  species  of  this  genus.  Certain  large  trees  at 
the  proper  period  of  the  year  were  repeatedly  covered  with  the  rust  and 
often  small  shoots  a  foot  or  so  high  would  have  each  leaf  completely 
rusted. 

Cotton.  Kriehneola  Gossypii.  Very  little  cotton  is  raised  in  Porto 
Rico.  This  rust  was  foimd  in  considerable  abundance  in  one  field,  though 
probably  not  doing  much  damage. 

Manihot.  Uromyces  Janiphce.  Only  one  collection  of  this  rust  was 
made  in  Porto  Rico,  though  the  host  is  very  common  there  under  culti- 
vation, and  the  rust  has  been  looked  for  repeatedly.    . 

Sooty  Molds.  The  sooty  molds  familiar  to  Northern  pathologists 
on  the  orange  and  CamelUa  and  to  lesser  degree  on  many  greenhouse 
plants,  aboimd  in  Porto  Rico.  There  seems  to  be  no  speciaUzation  to 
hosts  and  they  grow  indiscriminately  upon  all  hosts.  If  it  be  a  large 
plant  as  a  mango  tree  that  is  primarily  infected,  the  fungus,  spread 
doubtless  by  rain,  is  found  growing  upon  every  kind  of  plant  beneath 
the  tree.  Very  Uttle  evil  eflFect  is  noticeable  other  than  the  imsightly 
condition  produced.  The  statement  is  frequently  seen  that  these  sooty 
molds  exist  upon  insects  or  insect  secretions.  Such  organic  matter  cer- 
tainly favors  them  and  increases  their  luxuriance,  but  the  sooty  molds 
are  not  entirely  dependent  upon  insects  and  insect  products  and  may 
aboimd  without  them. 

While  many  of  the  Porto  Rican  sooty  molds  are  much  like,  perhaps 
quite  like,  the  sooty  mold  of  the  orange,  other  sooty  molds  diverge  more 
or  less  from  this  in  character,  yet  show  similarity  enough  among  them- 
selves to  allow  them  to  be  classed  in  the  same  group. 

The  writer  has  so  far  refrained  from  using  latin  names  for  these  fungi. 
The  orange  and  camellia  sooty  molds  are  best  known  under  the  generic 
name  Meliola,  and  the  generic  conception  of  Meliola  was  broad  enough  to 
receive  them  imtil  about  1892.  Gaillard's  monograph  of  MeUola  then 
showed  that  these  forms  clearly  differ  greatly  from  the  typical  Meliolas 
in  essential  details,  and  he  excluded  from  Meliola  the  tropical  sooty 
molds.  Today  any  student  of  Meliola  would,  I  think,  agree  with  him. 
Meliola  with  its  capitate  and  mucronate  hyphopodia,  its  characteristic 
mjrcelium,  perithecia,  asci  and  spores  constitutes  a  well-defined  genus 
from  which  the  sooty  molds  with  their  bead-like  mycelimn,  peculiarly 
shaped  pycnidia  and  perithecia  diflFer  widely.    The  fact  that  they  should 


134  PHYTOPATHOLOGT  [VOL.  7 

be  excluded  from  Meliola  is  clear.  Jiist  where  they  should  be  placed  is, 
however,  not  so  clear.  They  comprise  a  rather  well-defined  group  which 
in  Porto  Rico  certainly  consists  of  a  large  number  of  species  on  many 
hosts.  This  group  perhaps  coincides  in  limits  with  what  Sacoardo  in  his 
earlier  volumes  calls  the  sub-family  Capnodiese  and  which  he  in  his 
foxuleenth  voltune  calls  a  tribe.  This  tribe  is  not  recognised  by  Lindau 
in  the  Naturlichen  Pflanzenfamilien/but  is  included  in  the  Perisporiacea. 
Clements  gives  the  Capnodiacese  family  rank.  Amaud  in  1911  in  his 
monograph  '^Contribution  a  Tetude  des  Fumagines"  Ann.  Ek^.  Nat. 
Agr.  Montpellier,  places  them  for  convenience  in  the  ''Spheriaoees  dic- 
tyosporecs."  Many  writers  today  place  the  better-known  of  these  forms 
of  the  habit  of  the  old  Meliola  Citri,  Meliola  CameUcB,  and  so  forth, 
in  the  genus  Capnodium.  Thus  we  have  C.  HeUatumf  C.  Mangtferum,  C. 
Coffe<Bf  C.  brasiliense,  C.  footie.  Others  place  these  forms  in  the  genera 
Pleosphseria,  Antcnnaria,  Apiosporiimi,  and  so  on.  It  is  not  the  pres- 
ent purpose  of  the  writer  to  attempt  to  determine  the  generic  limits 
here  or  the  status  of  these  species,  but  rather  to  call  attention  to  the 
rich  mass  of  material  occurring  in  the  tropics,  which  may  well  be  called 
the  Sooty  Molds  and  in  the  main  belong  to  the  Capnodies  of  Sacoardo. 
Illinois  U.niversity 

Urbana,  Illinois 


PYCNIAL  STAGES  OF  IMPORTANT  FOREST  TREE  RUSTS 

James  R.   Weir  and   Ernest  E.   Hubert 

With  Two  Fiqubes  in  the  Text 

The  discovery  on  September  29,  1916,  at  Darby,  and  on  October  8, 
/916,  at  Bonner,  Montana,  of  abundant  exudations  of  pycnospores  on 
swellings  of  Pinus  panderosa  (fig.  1)  and  Pinus  contorta  caused  by  Cronar- 
Hum  Comandrce  Pk.  somewhat  alters  the  impression  that  the  pycnia  of  the 
caulicolous  species  of  forest  tree  rusts  appear  only  during  the  spring  or 
early  summer  months.  This  \musual  appearance  of  pycnospores  seems 
to  be  of  sufficient  importance  in  the  life  history  of  this  rust  to  be  re- 
ported at  this  time  together  with  further  facts  concerning  the  pycnial 
stages  of  Cronartium  coleosporoides  (D.  &  H.)  Arthur,^  Cronartium  Comp- 
tonicBy^  Arthur  and  Cronartium  cerebrum  (Pk.)  H.  &  L.  Spaulding*  in  his  ac- 
coimts  of  the  white  pine  blister  rust  {Cronartium  ribicola  Fisher)  states  that 
the  pycnial  stage  may  be  found  early  in  the  spring  or  at  almost  any  season 
in  late  summer  or  fall,  he  having  foimd  them  on  the  hosts  in  November 
within  a  month  after  placing  in  the  greenhouse.  The  collections  of 
Cronartium  Comandroe  on  Pinus  ponderosa  and  P.  contorta  bearing  the 
pycnial  stage  were  of  the  spindle-shaped  tjrpe  of  swellings  and  bore  in  the 
central  portion  cankerous  corrugations  of  the  current  season's  (May, 
1916)  aecial  eruptions.  The  pycnial  drops  appeared  on  the  freshly 
swollen  areas  at  either  end  of  the  spindle-shaped  hjrpertrophies  bordering 
the  ruptured  areas.  This  conforms  to  observations  made  on  a  collection 
of  the  pycnial  drops  made  near  Bonner,  Montana,  on  May  22,  1916, 
from  lesions  of  Cronartium  ComandrcR  on  Pinus  ponderosa.  The  pycnial 
exudations,  consisting  of  a  clear,  sticky,  sweet  liquid  with  a  large  num- 
ber of  minutely  pyriform  spores  in  suspension,  appear  as  large  or  small 
drops  issuing  from  minute  blister-Uke  swellings  in  the  epidermis  of  the 
infected  tissues.  Measurements  of  the  pycnospores  of  the  various  col- 
lections made  agree  closely  with  those  made  by  Boyce,*  (50)  3  to  4  m  by 

•  Weir,  J.  R.  and  Hubert,  E.  E.  Recent  cultures  of  forest  tree  rusts.  Phyto- 
path.  7: 106-109.    1917. 

•  Spaulding,  Perley.  The  blister  rust  of  white  pine.  U.  S.  Dept.  Agr.  Bur. 
Plant  Ind.  Bui.  206:  27-28.    1911. 

.    The  white  pine  blister  rust.    U.  S.  Dept.  Agr.  Farmer's  Bui.  742:  12. 

1906. 

•  Boyce,  J.  S.  Pycnia  of  Cronartium  pyriforme.  Phytopath.  6:446-447.  D. 
1916. 


136  Phytopathology  [Vol,  7 

3  to  7  M  (3  by  4).  They  are  characteristically  pyriform,  of  a  pale  turtle 
gre<'n  color^  issuing  from  minute  openings  in  the  epidermis  and  are  pro- 
duced from  8ul)epidermal  pycnial  stromata  of  irregular  outline.  Boyoe 
states  that  the  pycnospores  are  hyaline.  An  examination  of  both  i«io- 
lated  and  massed  spores  indicates  that  they  are  colored,  thoiigh  faintly. 
The  pycnial  stages  of  Cronariium  coleosporaides  and  Cranariium  Comp- 
lonicB  have,  up  to  the  present,  remained  unknown.  Mention  of  the  dis- 
cover}' of  the  stage  has  been  made  in  a  previous  report*  but  details  were 
not  given  at  tliat  time.  In  the  period  from  April  4  to  15,  1916,  abimdant 
pycnial  exudations  containing  pycnospores  were  obtained  from  galls  of 
Crofiartium  coleosporaides  (fig.  2)  on  Pinus  ponderosa  and  P.  cantoria. 
These  pycnial  dmps  were  found  in  the  field  and  were  also  forced  in  the 
lalK>ratory  at  a  much  earlier  date  than  produced  in  nature.*  Out  of  a 
total  of  32  galls,  28  proiluced  pycnia  by  the  forcing  process,  several  of 
these*  lat^r  producing  aecia.  The  pycnia  of  Cronartium  coleosporaides  on 
galls  develop  similarly  to  those  of  Cronariium  Comandras  with  one  marked 
diff(»n»nce,  that  is,  their  appearance  on  old  galls  and  legions.  The  pycno- 
spores of  Cronariium  Camandrce  apparently  develop  but  onoe  on  the  same 
tissue  prc'ceding  the  appearance  of  the  aeciospores.  The  production  of 
aecia  kills  the  infected  tissues  which  are  included  in  the  aecial  ruptures. 
The  tissues  lK)rdering  this  area  are  invade<l  by  the  mycelium  of  the 
fungus,  produce  swellings,  and  give  rise  to  pycnospores,  either  in  early 
spring  or  in  late  simimer  and  fall,  whenever  sufficient  time  has  elapsed 
from  the  last  prcxluction  of  aecia.  In  the  cases  recorded  the  pycnospores 
appt^ired  in  the  same  season  following  the  pnxluction  of  aecia,  with  only 
five  months  intervening,  but  not  from  the  identical  area  from  which  the 
pycnia  were  pr<Hluced.  In  Cronariium  coleosporaides  the  pycnospores 
an*  pr(Kluce<l  on  ol<l  galls  previously  ruptured  as  well  as  on  unruptured 
infert<»<l  tis^nies.  A  description  of  the  pycnia  of  Cronariium  coleosporoideM 
on  galls  follows: 

Pyrnial  iitroma  in  irroi^ularly  Hhapini  aroAi«,  more  or  less  scattered  or  anasto- 
moflinK.  raulirolouM,  subepitlemial,  forming  minute,  blister-like  swelliDgs  when 
mature  <m  unruptured  infecte<i  tiMuofl  and  iiwuinK  from  cracks  in  the  bark  of  old 
le^ionfl;  exuding  a  dear,  ffueet.  stieky  fluid  in  which  the  pycnosporee  are  suspended 
forming  dropfi  of  a  ca<imium  yellow  to  orange  color  when  first  appearing,  l»ecomins 
clear  aM  the  Hpore  maj«ti  KettleM  to  the  lower  end  of  drop,  and  orange  to  brick-red 
ufxm  drying.  PyrnoxporeH  hyaline,  mostly  spherical,  occasionally  ellipsoid  or 
olM»vttte      i,V)    1.5  to  U.O  M  by  1.5  to  3.7  /i  (2.5  by  2.5). 


*i<idg<'v%a>.  HnlMTt.     Color  ^t:indlird•«  and  color  nomenclature.     PI.  32.     1912. 
•  Phyt<.path   7:  Un't  10l».     11U7. 
'   The  -aine. 


1917]  Weir  and  Hubert:  Pycnial  Stages  of  Rusts  139 

from  the  field  bore  remnants  of  the  pycnial  exudations  and  at  the  same 
time  were  producing  aecia  in  abimdance.  The  pycnial  drops  when  fresh 
have  a  slightly  darker  yel'ow  color  than  those  of  Cronartium  coleosparoidea, 
and  like  the  latter  appear  in  the  bark  crevices  of  old  galls  as  well  as  in 
minute  blister-like  swellings  on  the  yoimger  unruptured  tissues  of  in- 
fected areas.  When  old  and  dried  the  pycnial  exudations  are  difficult  of 
detection  on  the  surface  of  the  infected  tissues  and  have  a  brick-red  color. 

From  observations  made  on  Cronartium  coleosporoides  on  galls  both 
in  the  laboratory  forcing  experiments  and  in  the  field,  it  is  determined 
that  the  aecia  follow  the  pycnia  in  the  same  season,  usualy  from  eight  to 
sixteen  days  apart  but  not  appearing  upon  the  identical  areas.  The 
galls  shown  in  figure  1  were  collected  at  Coeur  d'Alene  April  1,  1916, 
and  were  placed  in  test-tubes  with  water  on  April  3.  From  April  4  to  9 
abundant  pycnial  drops  were  produced.  From  April  11  to  14  the  galls 
began  to  show  evidence  of  aecial  eruptions  and  from  April  16  to  17  aecia 
appeared.  With  a  longer  time-interval  between  the  two  stages  this  is 
what  has  been  observed  to  occur  in  the  field.  Spaulding^  has  observed 
in  the  case  of  Cronartium  ribicola  that  the  pycnia  precede  the  aecia  by  a 
short  period. 

A  very  interesting  fungus  frequently  foimd  during  the  past  season  in 
connection  with  the  pycnial  exudations  and  also  foimd  accompanying 
the  aecial  stage  of  the  caulicolous  rust  is  a  species  of  Tuberculina  which 
may  be  referred  to  T.  maxima  Rostrup.*  This  fungus  was  found  at- 
tacking the  pycnial  and  aecial  stages  of  Cronartium  Comandrce  occurring 
on  PiniAS  ponderosa  and  P.  contorta,  the  pycnial  and  aecial  stages  of  Cro- 
nartium coleoaporoidea  on  galls  of  PiniLS  ponderosa  and  P.  contorta,  and  the 
pycnial  and  aecial  stages  of  Cronartium  cerebrum  on  Pinua  bankeiana. 
This  species  of  Tuberculina  attacks  the  stromatal  layer  as  well  as  the 
fruiting  bodies  and  erupts  in  powdery,  Hlac  to  nigrosin  masses  through  the 
epidermis  of  the  host  tree.  This  fiuigus  is  considered  by  Tubeuf  •  to  be  of 
some  economic  importance  although  Lechmere^®  does  not  concur  in  this 
conclusion.  The  writers  have  not  found  it  occurring  in  sufficient  abun- 
dance  to  place  any  importance  upon  its  economic  possibilities. 

Office  of  Investigations  in  Forest  Pathology 
Bureau  of  Plant  Industry 
Missoula,  Montana 

»  U.  8.  Dept.  Agr.,  Bur.  Plant  Ind.  Bui.  206:  27-28.     1911. 

•  Tubeuf,  C.  von.    Ueber  Tuberculina  maxima,  einen  Parasiten  des  Weymouth- 
skiefem-Blasenrostes.    Biol.  Abt.  f.  Land-  u.  Forstwirthschaft.  2: 169.    1901. 

*  Tubeuf,  C.  von.    Recent  observations  on  the  blister  rust  of  Weymouth  pine. 
Naturw.  Ztochr.  Forst.-u.  Landw.  12:  484-491.    1914. 

^*  Leohmere,  E.    Tuberculina  maxima,  a  parasite  on  the  blister  rust  fungus  of 
the  Weymouth  pine.    Naturw.  Ztschr.  Forst.-  u.  Landw.  12:  491-498.    1914. 


REVIEWS 

Edible  and  Poisonous  Mushrooms.    By  W.  A.  MurriU,  Afisistant  Director 

of  the  New    York   Botanical    Garden.     Handbook,    IGmo.,  pp.    71, 

large  colore^l  chart,  figs.  47.     Published  by  the  Garden.    Price  $2. 

This  work  is  primarily  of  interest  to  users  of  mushrooms.    Tlie  chart 

contains  very  good  illustrations  of  30  species  of  edible  mushrooms,  and 

of  17  species  of  poisonous  ones.     A  few  of  these  are  of  interest  to  the 

forest  pathologist,  Ix^cause  they  frequently  attack  the  wood  of  living  trees. 

Geo.  G.  Hedgcock 

PHYTOPATHOLOGIC'AL  NOTES 

Sew  hosts  for  Razoumofskya  americana  and  R.  ocddenlalis  abieiina, 
Rdzoumofskya  americana  Nutt,  has  l)een  previously  reported  on  PinuM 
coniorta,  P.  banksiana,  P.  jwnderosa,  and  P.  jeffreyi.  On  April  12,  1915, 
a  specimen  was  received  from  J.  K.  Haefner  of  the  Sifiki>'OU  National 
Forest,  Oregon,  on  Pinus  attenuata.  On  Septeml)er  5,  1916,  the  writer 
collected  l>oth  staminate  and  pistillate  plants  on  Pinus  aUenuaia  in  the 
Oregon  Mountains,  Siskiyou  Forest.  This  indicates  that  the  species  may 
1h»  exi)ecte<l  to  occur  on  any  of  the  yellow  pines.  (See  writer's  note. 
Phytopath.  6:  414.     1916.) 

Razoumofskya  occi4ientalij<  nhietina  (Kngelm.)  (V)ville,  the  large  form  on 
Abies.  ha.»<  Ihh^ii  rei>orted  on  Abi4's  concoloTy  A,  grandis^  and  A,  magnificat 
During  a  trip  on  the  Oater  National  Forest,  Oregon,  in  Septeml)er,  1916, 
the  writer  <*ollertcHl  iM>th  staminate  and  pi.stillate  plants  on  Abies  nobilis 
and  .4.  amabilis. 

James  K.  Weir 

Lighttiing  injury  to  kale.  In  a  previou.s  article  (Phytopath.  S:  IM. 
191'))  the  writer,  jointly  with  (SillH^rt,  reiK)rt<»<l  ol)8erv'ation8  upon  light- 
iiiiit;  killing  of  |N)tat<H\«<  and  <*ottoii.  As  sliown,  the  plants  in  the  stricken 
zone  die  j)roniptly  over  a  somewhat  eireular  area  usually  fnmi  one  to 
three  nnU  in  diiiineter.     Further  evidence*  of  this  sort  of  injur}*  in  Wis- 

*  Ilo«lKt*'><4c.  (>.  (f.  N(»t("*  on  florne  dineimiM  of  trees  in  our  national  foreau.  V. 
Phytopath.  6:  I7«».      I'M.V 

Wi«T,  J.  K.  .MiMtlctfM*  injury  to  conifi*rH  in  the  northwest.  U.  S.  Dept.  Afr. 
Bui.  :WM):  33.     1910. 


142  Phytopathology  [Vol.  7 


of  the  storm  were  rather  small  and  all  had  the  appearance  of  having  beeo 
struck  by  some  strong  force  and  flattened  to  the  ground,  and  the  three 
plants  which  seem  to  be  inside  the  circle  and  have  survived  were  ahnost 
completely  covered  with  earth.  The  rest  of  the  plants  in  the  circle  had 
a  powder-burned  appearance  and  all  shrivelled  up  and  disappeared  within 
a  week  or  ten  days."  The  area  as  shown  in  the  figure  was  roui^y 
circular,  about  twenty  to  twenty-five  feet  in  diameter.  This  accords 
closely  in  all  respects  with  the  effect4s  of  the  lightning  strokes  as  we  have 
observed  them  in  Wisconsin  potato  fields. 

It  is  to  be  hoped  that  others  may  record,  as  they  have  opportunity, 
evidence  of  such  injuries  imtil  we  have  a  fuller  imderstanding  of  these 
matters.  From  the  e\adence  at  hand,  similar  injuries  may  be  expected 
with  sugar  and  garden  beets,  and  possibly  carrots,  with  the  varioiis  mem- 
bers of  the  cabbage-kale  groups  of  vegetables,  turnips,  radiahee,  and  so 
forth,  and  probably  with  the  allies  of  the  potato,  such  as  tomato  and  egg 
plants.  Special  attention  may  also  well  be  given  to  possible  li^^tning 
injury  of  legumes  in  view  of  Sitensky's  observations.  (See  Abstract, 
SSeitschr.  Pflkr.  8:  148,  1898),  which  have  come  to  my  attention  since 
our  former  article.  He  reports  a  lighting  stroke  in  a  Bohemian  alfalfa 
field  when  the  plants  were  in  blossom.  The  next  day  the  plants  were 
wilted  down  in  a  circular  area  about  5  meters  across. 

It  is  noteworthy  that  no  case  is  recorded  of  like  injury  with  any  of  the 
Gramineae,  although  it  would  seem  that,  since  great  areas  are  occupied 
by  the  grains  and  grasses  in  the  northern  states,  lightning  must  often 
strike  in  such  fields.  When  more  evidence  is  at  hand  conoeming  the 
varying  liability  of  such  plants  to  injury  in  nature  it  will  pave  the  way 
to  some  very  interesting  experimental  work  to  determine  the  reasons 
why  such  variations  occur.  These  may  conceivably  be  associated  with 
differences  in  the  character  or  habit  of  aerial  parts,  with  the  character  or 
distribution  of  the  root  systems,  or  with  the  relative  electrical  conductivity 
of  the  different  plant  tissues. 

L.  R.  Jones 

Puccinia  glumarum.  In  May,  1915,  the  occurrence  of  Pucdnia  glu-^ 
marum  (Schmidt)  Rriks.  and  Henn.  was  reported  for  the  first  time  in  the 
Tnited  States.  It  is  so  well  known  in  Kurope  and  certain  Asiatic  countries 
thiit  it 8  discover^'  at  ho  many  widely  distant  points  in  the  western  states 
led  to  considerable  speculation  as  to  time  and  method  of  introduction  into 
America.  Although  we  are  Htill  lacking  definite  information  on  these 
points,  it  is  now  definitely  kn<mii  that  an  examination  of  herbarium 
s|XM*imen8  at  the  New  York  liotanic  (iunlens  indicates  the  fact  that  P. 
glumarum  was  collected  in  this  country  as  long  ago  as  June,  1892,  when 


1917]  Phytopathological  Notes  14S 

C.  V.  Piper  reported  it  as  P.  rubigo-vera  on  Elymus  americanus  and  a 
month  later  as  P.  rvbigo-vera  on  Bromus  hookerianusy  and  distributed  it 
under  numbers  41  and  206.  These  specimens  were  found  at  Seattle  and 
Everett,  Washington,  respectively. 

Other  American  collections  of  Puccinia  glumarunij  made  prior  to  1915^ 
were  by  E.  T.  and  E.  Bartholomew  in  August,  1913,  at  Billings,  Mont., 
on  Hordeum  jubatum  under  number  4369;  E.  Bartholomew  on  Hcrdeum 
jubatum  at  Rock  River,  Wyo.,  in  August,  1911,  under  nmnbers  1063 
and  3763,  and  by  A.  O.  Garrett  in  1907  and  1909  in  Utah  and  distributed 
as  P.  rubig(M)era  imder  numbers  138,  191,  and  192. 

It  would  thus  appear  that  Puccinia  glumarum  has  been  present  in 
America  at  least  twenty-five  years  and  possibly  longer. 

H.  B.  Humphrey 

Newton  B,  Pierce,  The  death  is  annoimced  on  October  13,  1916,  at 
the  age  of  sixty  years,  of  Mr.  Newton  B.  Pierce,  formerly  pathologist  in 
the  Bureau  of  Plant  Industry. 

Mr.  Pierce  in  his  early  manhood  was  engaged  in  the  lumber  business, 
in  partnership  with  his  brother  at  Ludington,  Mich.  He  was  from  a  boy 
interested  in  natural  history  and  spent  a  great  deal  of  his  time  in  the 
woods.  At  first  he  turned  his  attention  to  economic  entomology,  and 
very  early  developed  into  an  excellent  entomological  artist.  He  was 
sp)ecially  gifted  in  the  field  of  draughtsmanship,*  particulary  in  the 
delineation  of  plants  and  insects.  Desiring  to  advance  his  knowledge 
along  entomological  lines  he  went  to  Harvard  and  took  up  some  special 
work  in  entomology.  Conditions  were  not  favorable  for  the  best  work, 
and  he  relinquished  his  entomological  studies,  and,  after  casting  about, 
decided  to  take  up  work  in  plant  pathology  under  Dr.  Volney  Spaulding, 
of  the  University  of  Michigan.  Largely  through  Dr.  Spaulding's  influ- 
ence, Mr.  Pierce  became  intensely  interested  in  plant  pathological  studies. 
He  developed  into  a  keen  observer  and  a  thorough-going  investigator. 

In  these  early  days  there  was  comparatively  little  pathological  work 
carried  on  in  this  country,  and  those  engaged  in  it  were  few  in  number. 
The  pathological  work  of  the  government  had  only  just  been  inaugurated. 

About  1887  or  1888  there  appeared  in  CaUfomia  a  serious  grape  disease, 
which  spread  rapidly  and  caused  immense  damage  to  the  vine  industry 
of  that  state.  Early  in  1889  the  disease  had  become  so  virulent  that  the 
Section  of  Vegetable  Pathology  in  the  U.  S.  Department  of  Agriculture 
decided  to  undertake  an  investigation  of  the  trouble.  In  casting  about 
for  someone  to  take  up  this  work  Professor  Spaulding  of  Michigan  was 
communicated  with.  He  reconunended  Mr.  Pierce,  and  Mr.  Pierce  was 
app>ointed.    Mr.  Pierce  proceeded  at  once  to  Santa  Ana,  CaUf.,  and  made 


144  Phytopathology  (Vol.  7 

that  place  his  headquarters.  He  began  at  once  a  careful  field  study  of 
the  disease.  After  six  or  eight  months  of  field  studies  he  decided  that 
he  wanted  to  go  abroad  in  order  to  get  a  line  on  the  diseases  of  the  grape 
in  the  south  of  France  and  in  Italy.  He  went  abroad  at  his  own  expense, 
and  was  away  six  or  eight  months.  Upon  his  return  he  renewed  his 
investigation  of  the  grape  diseases,  and  eight  or  nine  months  later  pub* 
lished  his  valuable  report  on  the  California  vine  disease.  Mr.  Pierce 
continued  grape  investigations  and  took  up  other  lines  of  work. 

Gradually  the  laboratory  at  Santa  Ana  grew  into  one  of  the  most 
important  branches  of  the  plant  pathological  work  of  the  government. 
The  name  was  changed  to  the  Pacific  Coast  Laboratory,  and  Mr.  Pierce 
was  put  in  charge.  He  remained  in  charge  of  this  work  until  December 
31,  1906,  when  he  resigned. 

During  Mr.  Pierce's  work  on  the  Coast  he  conducted  important  in\'e0ti- 
gations  in  the  California  vine  disease,  leaf  curl  of  the  peach,  walnut  bli|^t, 
and  the  diseases  of  the  grape. 

Mr.  Pierce  was  a  man  of  quiet  and  unassuming  habits.  He  was  pre* 
eminently  an  investigator,  and  preferred  to  work  alone.  A  careful  study 
of  the  record  of  his  accomplishments  on  the  Pacific  Coast  will  show  that 
he  was  an  indefatigable  and  earnest  student. 

B.  T.  Galloway 

Pathological  greenkoxue.  On  the  basis  of  the  presentation  in  Pryto* 
PATHOLOGY  for  February,  1916,  of  the  need  for  controlled  greenhouse 
conditions  in  Imtanical  research  (Potter,  Alden  A.  The  control  of  experi- 
mental conditions  in  ph>'topathological  research,  p.  81)  funds  have  been 
secured  for  carrying  out  these  ideas  in  connection  with  the  investigations 
of  the  Bureau  of  Plant  Industr\'  on  the  cereal  rusts,  and  it  is  hoped  to 
have  at  Ic^st  one  unit  of  this  apparatus  in  operation  in  Washington  within 
the  present  year. 

Cereal  rtui  nurvey.  An  extensive  barberry  and  cereal  rust  field  survey 
is  projecte<l  for  the  coming  spring  and  summer  by  the  Office  of  Cereal 
Investigations,  Bureau  of  Plant  Industry. 

PernonaU,  Dr.  J.  L.  Wcimer,  formerly  assistant  in  the  Department  of 
Botany  of  Purdue  l*niversity,  I^fayette,  Indiana,  has  been  appointed 
scientific  assistant  in  the  Bureau  of  Plant  Industr>',  effective  February  14, 
to  take  up  work  on  the  diseases  of  sweet  potatoes  and  other  truck  crops. 

Mr.  Moses  Irvine,  assistant  in  the  Department  of  Botany  and  Plant 
Patholog\\  Tniversity  of  Minnesota,  has  recently  Ixren  appointed  assistant 
in  Plant  Patholog>'  in  the  Kansas  Agricultural  College,  Manhattan,  Kan. 


REPORT  OF  THE  EIGHTH  ANNUAL  MEETING  OF  THE 
AMERICAN  PHYTOPATHOLOGICAL  SOCIETY 

The  eighth  annual  meeting  of  the  Society  was  held  in  Barnard  College,  Columbia 
University,  New  York  City,  N.  Y.,  December  27-30,  1916,  in  conjunction  with  the 
American  Association  for  the  Advancement  of  Science. 

About  ninety  members  were  present  and  a  program  of  eighty-three  papers  was 
presented,  the  abstracts  of  which  appeared  in  the  last  number  of  Phttopathologt. 
Twenty-four  new  members  were  elected,  making  a  total  of  three  himdred  and 
sixty-seven. 

Joint  sessions  were  held  with  Section  G  of  the  American  Association  for  the 
Advancement  of  Science  and  also  with  the  Botanical  Society  of  America. 

The  following  officers  were  elected: 

Presidentf  Dr.  Mel.  T.  Cook,  Agricultural  Experiment  Station,  New  Bnmswick, 
N.J. 

Vice-PrenderUf  Dr.  Charles  Brooks,  U.  S.  Department  of  Agriculture,  Wash- 
ington, D.  C. 

Councilor  for  three  years t  Prof.  H.  S.  Jackson,  Purdue  University  Agricultural 
Experiment  Station,  Lafayette,  Ind. 

One  of  the  Chief  Editors  of  Phytopathology  for  three  years,  Dr.  G.  P.  Clinton, 
Agricultural  Experiment  Station,  New  Haven,  Conn. 

AssociiUe  Editors,  J.  B.  Rorer,  Port-of-Spain,  Trinidad;  Prof.  H.  P.  Barss,  Ore- 
gon Agricultural  College,  Corvallis,  Ore. ;  Dr.  Geo.  M.  Reed,  University  of  Missouri, 
Columbia,  Mo.;  and  Dr.  H.  A.  Edson,  U.  S.  Department  of  Agriculture,  Wash- 
ington, D.  C.  * 

The  Society  decided  to  hold  its  next  annual  meeting  at  Pittsburgh,  Pa.,  in  con- 
junction with  the  American  Association  for  the  Advancement  of  Science,  Deoeniber 
28,  1917,  to  January  2,  1918. 

AMENDMENT  TO  THE  CONSTITUTION 

Article  II,  Section  1,  line  1,  after  the  word  "include"  the  word  sustaining  was 
inserted. 

Article  III,  Section  3,  line  1,  after  the  word  "become"  a  sustainxhg  life  member 
by  paying  one  hundred  dollars  in  ten  conseciUive  annual  payments  was  substituted  for 
"a  life  member  upon  the  payment  of  fifty  dollars." 

BEPORT8  OF  COMMITTEES 

The  Committee  on  Common  Names,  consisting  of  F.  C.  Stewart,  G.  P.  Clinton, 
F.  L.  Stevens,  E.  C.  Stakman,  and  W.  A.  Orton,  presented  the  following  report  and 
recommendations: 

Carrying  out  the  instructions  of  the  Society  at  the  Columbus  meeting,  the  Com- 
mittee sent  copies  of  the  partial  list  of  conmion  names  which  it  had  prepared  to 
about  200  memoers  of  the  oocietv  for  their  criticisms.  In  consequence  of  the  sug- 
gestions received  the  Committee  has  made  some  changes  in  the  list  and  30  names  have 
been  stricken  from  the  list.  The  revised  list  contains  the  names  of  17  host  plants 
(alfalfa  to  cabbage)  and  92  diseases.    The  adoption  of  this  list  is  recommended. 

The  Committee  reconmiends  further  that  this  work  on  common  names  be  con- 
tinued under  the  following  plan: 


146  Phytopathology  [Vol.  7 

• 

(1)  The  American  Phytopathological  Society  shall  officially  adopt  a  list  of 
common  names  of  plant  diseases. 

(2)  There  shall  t>e  a  oermanent  standing  committee  of  the  Society,  called  the 
Committee  on  Common  Names  of  Plant  Diseases,  consisting  of  five  membera,  one 
memlier  being  elected  by  the  Council  each  year  to  serve  five  years.  The  Cammittee 
shall  elect  its  own  officers.  The  meml)crs  of  the  present  Committee  (1916)  shall 
retire  in  the  order  of  the  length  of  service  of  each.  A  vacancy  on  this  Committee 
shall  be  filled  temporarily  by  appointment  of  the  President  of  the  Society,  the  ap> 
pointee  to  serve  until  the  next  annual  meeting,  at  which  time  the  Council  shall 
elect  a  meml)er  to  complete  the  unfinished  term. 

(3)  This  Committee  shall  prepare  and  present  to  the  Society  for  official  action 
at  the  regular  annual  meeting  a  list  of  common  names  of  plant  diseases,  and  at  each 
succeeding  annual  meeting  a  supplementary  list  of  names  may  bo  presented.  At 
least  six  weeks  l)efore  the  annual  meeting  the  Committee  shall  submit  a  preliminary 
list  of  names  to  all  nieml)er8  of  the  Society  for  suggestions  and  criticiam  in  writing. 
At  the  l)eginning  of  the  annual  meeting  the  revised  list  shall  be  conapicuousiy 
posted  to  invite  further  HUggentions  and  criticisms.  The  list  as  finally  revised  by 
the  Commit tei»  shall  In*  presented  to  the  Society  at  the  same  annual  meeting  for 
final  adoption.  The  list  of  names  officially  adopted  at  each  annual  meeting  shall 
l¥»  printed  in  Phytopathouhjy  in  the  n^port  of  the  meeting  of  the  Society.  The 
official  list  may  lx»  amended  undrr  the  same  procedun*. 

I'lKin  motion  the  report  was  arcepte<l  an<l  the  recommendations  adopted.  Later, 
in  connection  with  a  diHcu.HMion  of  the  propo.sed  list  of  common  names  which  the 
Committee  ha<i  prepan»<l,  a  motion  to  reron.Hider  the  action  in  regard  to  the  report 
of  the  (^ommittfH*  wa^^  adopted,  and  a  moti<m  waM  made  and  carried  that  the  (*ora- 
mittet*  be  in»<tnirte<l  to  submit  to  the  entire  membership  of  the  Society  by  mail  the 
list  of  common  nafncM  which  it  approve<l  and  to  re<]ueHt  a  vote  for  or  against  each 
name  propose<l,  a  three-fourths  majority  of  the  total  membership  being  necessary 
for  adoption  of  any  name.  \  motion  was  also  adopted  authorising  the  Committee 
on  (\»mmon  NamoM  to  change  the  above  plans  to  make  them  accord  with  the 
alNive  motion. 

('.  \^.  Kdgerton  was  ap|M>intcMl  tm  the  C<»mniittee  in  place  of  O.  P.  Clinton,  whoee 
term  expiriMl.  Since  the  close  of  the  meeting  F.  C.  Stewart  and  F.  L.  Stevens  have 
resigne<l  and  the  PreHident  has  ap|M)inted  in  their  places  (i.  H.  L>'man  and  J.  B.  8. 
Norton. 

The  (*tfmmittt'e  ttn  Wnt^  and  Means,  consisting  of  L.  H.  Jones,  C.  L.  Shear,  C.  W. 
Kdgerton,  H.  S.  Jackson,  and  J.  T.  Barrett,  di<l  not  report,  the  Chairman  being 
al>f«ent. 

The  Committee  **ri  liiUliography,  consisting  of  L.  U.  Jones.  C  L.  Shear,  and  R.  A. 
Harper,  mafli'no  fonnal  re^mrt.  C.  L.  Shear  stated  that  the  (Committee  had  been 
unable,  after  two  years'  effort,  to  wcure  the  fifty  subscribers  necessary  for  publica* 
tion  of  the  propos4*<i  card  in<lex  to  phytopathological  literature.  It  had  been  the 
exfMTtation  of  the  Conunitte<*  that  a  large  profHirtion  of  the  agricultural  colleges  and 
expf*rinM*nt  stations  would  subsrribe  for  the  index,  but  only  ten  such  sulMcriptioofl 
hail  lH*4*n  obtaintsl.  The  informal  report  was  accepted  and  the  Committee 
disrhargfHl. 

Tht  Cnmmittee  nn  the  Schirrinit:  (%tUection  of  Fungi,  consisting  of  C.  L.  Shear, 
3.  ('.  Arthur,  and  \.  (i.  Johnson,  made  a  report  of  pn»gresfl  to  the  effect  that  the 
(*urat<ir  of  the  Herbarium  had  offfred  to  take  whatever  steps  were  feasible  to  ae- 
romplir«h  th«*  pur|M>se  desirc^l  by  the  S<N<iety.  It  is  hop<Kl  to  |>erfect  the  details  and 
havr  th»"  matter  satisfactorily  atten<le«l  to  during  the  prosent  year. 

Thr  Cirmmittte  on  InMitutional  Stamiardisation,  c<msisting  of  H.  S.  Reed,  H.  H. 
Whi'txd.  an<l  H  H.  Fulton,  premMittMl  no  re|>ort  and  re<pi(*st<Ml  that  it  be  discharfed. 
Thr  r»'<|U»*st  was  approve<l  by  the  Society. 


1917]  New  York  Meeting  147 

The  Committee  on  Summer  Meetings,  consisting  of  Paul  Murphy,  E.  C.  Stakman, 
and  Donald  Reddick,  presented  no  report,  the  Chairman  being  absent. 

The  Committee  on  Pure  Culture  Supply  Laboratory,  consisting  of  C.  L.  Shear,  L. 
R.  Jones,  and  G.  P.  Clinton,  made  a  report  of  progress,  and  stated  that  an  item  had 
been  introduced  in  the  appropriation  bill  for  the  Bureau  of  Plant  Industry  for  the 
next  fiscal  year  to  cover  the  inauguration  of  this  work.  Whatever  is  accomplished 
in  this  direction  during  the  year  will  depend  upon  the  fate  of  this  appropriation. 

tbeasurer's  report 
Receipts: 

Balance  from  1915 $655.64 

Dues  of — 

268  regular  members  for  1916 $804.00 

72  sustaining  life  members 720 .00 

9  members  for  1915 27.00 

1  sustaining  life  member 100.00 

Overpayment  3  members 9.00        1,660.00 

Exchange  from  8  members. 1 .22 

Interest 15.64 

Excess  transfer  from  Society  funds 5.00    $2,337.50 

Expenditures: 

Approp'riation  to  Phytopathology  1915,  and  1916 400.00 

Clerical  work  (inc.  $14.80  for  1915) 73.43 

Printing  abstracts,  stationery,  etc 185.07 

Secretary's    traveling    expenses    to    attend   Columbus 

meeting ^ 44.28 

Mimeograph  work  for  F.  C.  Stewart 15 .00 

Supplies 7.75 

Exchange  on  checks .40 

Excess  dues  from  3  members 9 .00 

Rebate  for  No.  1,  Vol.  V,  exhausted .50 

Sinking  fund  for  Phytopathology 501 .58 

Telegrams 1 .55 

Transfer  to  Phytopathology  acct.  members 969.00      2,207.56 


Balance $129.94 

FINANCIAL  STATEMENT  OF  BUSINESS   MANAGER  OF   PHYTOPATHOLOGY 

Receipts: 

Balance  from  1915 $47.91 

Advertising  guarantee  1915 150 .00 

Subscriptions  and  sales  Phytopathology 620.38 

Annual  dues  transferred  account — 

9  members  for  1915 $  18.00 

268  regular  members,  1916 536.00 

72  sustaining  members  (1  excess) 360.00 

1  sustaining  member  in  full 50.00 

1  member  who  paid  $10 5.00  969.00 


148  Phytopathology  |Vol.  7 

Sales  Phytopatholoot  direct 18. 10 

Neiberg  subscription  (sent  to  W.  A  W.) 3.25 

Extra  illustrations  in  PHYTOPATHOLoaY,  O'Gara  and 

Hotaon 11 .28 

Annual  appropriation  from  American  Phytopathological 

Society  for  1916 200.00 

Interest  on  deposits .84 

Interest  on  mortgage,  6  months 15.00    $2,035  75 

Expenditures: 

Cooke  portrait S26.00 

Separates  from  Phytopathglooy 41 .05 

Stationery,  express,  postage  (Dr.  Reddick) 35.00 

Phoenix  files .57 

Illustration  of  horse-chestnut 10.00 

Readjustment  of  dues  one  member  paid  to  publishers  . .  3.00 

Readjustment  Neiberg  subscription,  paid  to  treasurer. .  3.25 

Insurance  on  stored  stock 5.40 

Manufacture  of  Phytopathology: 

No.  6,  Vol.  V,  balance  from  1915 $65.80 

No.  1,  Vol.  VI 432  82 

No.  2,  Vol.  VI 348.52 

No.  3,  Vol.  VI 338.78 

No.  4,  Vol.  VI 260  92 

No.  5,  Vol.  VI 165  82 

No.  6,  Vol.  VI,  $147.30,  pending 000  00        1.612.66 

Williams  A  Wilkinn  mii«cellaneou8  bills  for  postage,  etc.  78.98 

riericalwork 70.43 

Reimbursement    American    Phytopathological    Society 

account  over-transfer 5.00      1,892  24 

Balance $143.52 

These  accounts  were  referred  to  an  auditing  committee,  consisting  of  A.  D. 
Selby.  R.  Kent  Beattie.  and  K.  C.  Stakman.  The  Committee  reported  that  they 
had  examine<l  the  arrounts  and  found  them  correct,  and  the  reports  were  adopted. 

RKHOLl'TIO.VH    ADOPTED 

A  Committee,  conHixting  of  II.  .\.  KdHon.  .\.  I).  Selby,  and  John  L.  Sheldon. 
was  ap|H>intfil  by  the  Society  to  draft  resolutionH  in  reganl  to  the  deaths  of  two 
members,  \V.  \.  Mnrtin  an<l  Vungyen  Young,  and  alno  of  Professor  T.  J.  Burrill. 
The  following  rem»hition»  were  pre.«M»nt«»<l: 

"HtfiUvfd,  That  whereaM  in  th<*  death  of  W.  .\.  .Martin,  of  lloulton.  Maine,  and 
VuriKyfii  Young,  of  Shanghai.  China,  the  American  Phytopathological  Society  has 
btMMi  <b'prive<l  of  t>»o  of  itn  menib«*rH.  the  Society  reconU  itM  sincere  regret  at  the 
taking  of  theMc  gentlemen. 

"That  whcrea-*  in  the  death  of  Profe?*Mor  T.  J.  Burrill.  of  the  Cniversity  of  Illi- 
nois, uho  (ir<«t  (ictnoii**trat<Hi  the  exintenci*  of  bacterial  di.'^eaMes  of  plants,  there  has 
bci-n  rrninv***!  .m  eminent  lea<ler  in  botanical  and  phytopathological  research,  the 
Anteriran  Phytopathological  Society  i'XpreK?«e?*  itM  nincere  regret  at  the  departure 
of  tliM  eminent  Kcholar  and  teacher,  anci  records  itM  appreciation  of  the  service 
renderwi  our  science  by  his  researches. 


1917]  New  York  Meeting  149 

"That  these  resolutions  be  filed  with  the  records  of  the  Society  and  printed  in 
Phytopathology." 

The  following  resolution  was  also  passed  by  the  Society: 

"Resolvedj  That  the  Society  express  its  deep  appreciation  and  gratitude  to  the 
local  Committee  and  the  members  of  the  Department  of  Botany  of  Columbia  Uni- 
versity for  the  excellent  facilities  provided  and  for  the  many  courtesies  extended 
during  the  meeting. 

MISCELLANEOUS  BUSINESS 

Upon  motion  the  Society  voted  to  appropriate  two  hundred  dollars  from  any 
available  funds  for  use  in  the  support  of  Phytopathology  for  1917. 

In  response  to  a  request  from  the  Botanical  Society  of  America  to  nominate  a 
member  of  the  American  Phytopathological  Society  for  the  editorial  board  of  the 
Botanical  Society,  Dr.  A.  G.  Johnson  was  reconmiended  by  the  Council.  The 
Society  approved  of  the  action  of  the  Council. 

The  Board  of  Editors  made  the  following  recommendations  in  regard  to  Phyto- 
pathology, and  these  were  approved  by  the  Council : 

(1)  That  no  article  be  accepted  which  is  written  in  simplified  spelling,  but  that 
in  the  case  of  words  which  have  two  or  more  forms  in  good  usage  strict  uniformity 
is  not  required,  but  the  shorter  and  simpler  forms  are  to  be  preferred. 

(2)  That  Phytopathology  be  issued  monthly  and  include  five  hundred  or  more 
pages  during  the  year,  the  price  of  the  Journal  to  members,  including  dues,  to  be 
four  dollars  and  to  subscribers  five  dollars  per  year,  the  increase  in  price  to  begin 
January  1,  1918. 

(3)  Space  of  one-half  page  or  more  at  the  end  of  long  articles  is  to  be  used  for  the 
publication  of  briefer  articles  or  notes  in  order  to  avoid  wasting  space. 

(4)  It  is  recommended  to  members  of  the  Society  that  they  refrain  from  pub- 
lishing original  matter  in  extension  publications,  weekly  news  letters,  and  other 
similar  publications  which  are  not  usually  preserved  and  permanently  filed,  also 
that  such  references  be  omitted  from  the  list  of  literature. 

(5)  Recommended  that  authors  of  phytopathological  papers  which  are  pub- 
lished in  proceedings  of  academies,  horticultural  societies,  and  other  publications  of 
limited  distribution,  prepare  abstracts  covering  the  original  matter  for  publication 
in  Phytopathology. 

Professor  J.  B.  S.  Norton  presented  a  plan  for  ''a  standard  chart  for  per  cent  es- 
timates" in  regard  to  injury  and  conditions  of  diseased  plants.  Upon  motion  this 
plan  was  referred  to  a  Committee,  consisting  of  L.  R.  Jones,  V.  B.  Stewart,  and 
H.  B.  Humphrey,  for  consideration  and  report  to  the  Society  at  its  next  meeting. 

Dr.  E.  W.  Allen,  Editor  of  the  Experiment  Station  Record,  in  response  to  the 
resolution  adopted  by  the  Society  at  its  last  meeting  requesting  that  titles  of  papers 
abstracted  in  the  Record  be  published  in  full  in  the  original  language,  stated  that 
after  full  consideration  of  the  matter  it  did  not  appear  practicable  to  adopt  the 
proposed  change. 

Dr.  Donald  Reddick,  Editor  of  Phytopathology,  presented  a  verbal  report 
calling  attention  to  some  of  the  matters  discussed  by  the  Board  as  reported  above. 

U]>on  motion  the  Society  directed  the  Secretary  to  publish  during  the  year  a  new 
membership  list. 

The  Secretary  called  attention  to  the  need  of  prompt  notice  of  change  of  address 
of  members,  in  order  to  avoid  inconvenience  and  loss  of  copies  of  the  Journal,  and 
unnecessary  expense  in  correspondence.  C.  L.  Shear, 

Secretary 'Treasurer 


REPORT   OF   MEETING  OF  THE  PACIFIC  DIVISION  OF  TUB 
AMERICAN  PHYTOPATHOLOGICAL  SOCIETY 

A  meeting  of  the  Pacific  Division  was  held  at  the  University  of  Caiifomia,  Berke- 
ley, December  28  and  29,  1916.  President  J.  T.  Barrett,  of  the  CitruB  EzperimeBi 
Station,  Riverside,  California,  presided  at  the  sessions,  while  Ralph  E.  Smith,  of 
Berkeley,  California,  acted  as  secretary  in  the  absence  of  W.  T.  Home,  of  Berkeley 
who  is  spending  a  leave  of  absence  in  Cuba.  At  the  business  session  of  the  Society 
the  following  officers  were  elected  for  the  coming  year: 

President f  H.  P.  Barss,  Corvallis,  Oregon. 

Vice  President,  James  McM urphy,  Leland  Stanford  Junior  University,  PkJo  Alto» 
California. 

Secretary-Treasurer,  W.  T.  Home,  Berkeley,  California. 

The  following  papers  were  presented: 
Apple  rosette.    M.  A.  Willis 

No  abstract. 
^11  Alternaria  blight  of  tomatoes  in  California.     Bruce  Douolas 

No  alMtract. 
Sour  rot  of  lemons.    Clayton  O.  Smith 

No  alMtract. 
Stem-end  decay  of  Valencia  oranges  in  transit.    Clatton  O.  Smith 

No  abstract. 
Some  effects  of  sulphur  on  soils.     H.  S.  Reed 

Sulphur  in  the  form  of  elemental  sulphur,  sulphides,  or  sulphates  is  widely  used 
as  a  fungicid«*.  Much  of  thiH  material  finds  its  way  eventually  into  the  soil.  Itm 
eflfert  as  a  soil  constituent  is  thrn*fon*  pertinent. 

Under  anaerobic  conditions  microorganisms  may  reduce  sulphates  to  sulphites 
or  8uIphi<ieH.  l>oth  of  which  are  toxic  to  vegetation.  Oxidation  processes  may  cob* 
vert  sulphides  and  elemental  sulphur  to  sulphates.  The  process  is  largely,  if  not  en* 
tirely.  due  to  biological  agencies.  If  the  oxidation  process  is  incomplete  sulphite* 
may  \n*  formed. 

The  hannful  effects  of  sulphur  are  mon>  common  in  soil  deficient  in  organic  mat- 
ter, or  in  MoilH  having  an  acid  reaction. 
Black-heart  dinea^e  of  the  apricot.     IIelkn  Czar.vecki 
StudifJi  on  Monilia.     Kditii  Philliph 

No  alwtract. 
MinctUnncoiu  obnervations.     Jamea  .NfcMrRPiiT 

No  nl»Htract. 
Thr  t  j/w  rimrntal  incfstigation  of  alleged  smelter  smoke  injury  in  CalattroM  County, 

i'tllxittrfiUl.      W.   W.  TUOMAS 

N«>  al»j»tr:irt. 
l*Uth\itc%fnt\*  rtlated  to  Phytophthora.     J.  T.  Bakrett 

Kor  Mime  tiiiif  three  MtrainH,  |M>rlui(M  diMtinct  species,  of  a  fungus,  whoee  asexual 
stAg«*»«  rcTM-iiiblf  vi-ry  rloHely  thow  of  l^ythiacyntis  citrophthora  Smith  dk  Smith,  have 
bet^n  uricifr  oliservation.    Thest*  stmins  differ  mainly  from  the  latter  funfue  in  that 


1917]  Berkeley  Meeting  of  Pacific  Division  151 

they  produce  in  culture  oospores  while  the  perfect  stage  has  not  3ret  been  reported 
from  any  culture  of  P.  citrophthora  isolated  from  any  variety  or  species  of  Citrus. 

Of  the  three  strains  mentioned,  one  was  isolated  from  decaying  apples  in  March 
1908  in  Illinois;  one  from  bark  of  a  young  apricot  tree  in  March  1916  in  California 
and  the  third  from  bark  of  an  avocado  tree  by  H.  S.  Fawcett  in  May  1914. 

A  comparison  of  the  three  forms  with  four  species  of  Ph3rtophthora  has  revealed 
a  very  close  similarity  of  the  oogonia,  oospores,  and  antheridia  to  those  of  P.  cactorum 
(Cohn&  Leb.)  Schroeter,  while  their  asexual  spores,  (sporangia  and  conidia)  differ 
mainly  in  the  manner  of  separating  from  the  hyphae. 

This  marked  similarity  of  their  sexual  organs  to  those  of  P.  caciarumf  and  of 
Iheir  sporangia  to  those  of  Pythiacystia  citrophthora  would  seem  to  indicate  a  close 
relationship  of  the  two  genera  Pythiacystis  and  Phytophthora. 
VaricUiona  in  Colletotrichum  glcBoaporioidea.    O.  F.  Burger 

Cultures  of  Colletotrichum  glceosporioides  were  isolated  from  different  Citrus  spe- 
cies in  California.  They  have  been  grown  on  six  different  media  and  each  strain  re- 
sponds differently  to  the  media.  The  size  of  the  spore,  depends  in  part  upon  the 
medium  used.  A  hundred  spores  of  each  strain  were  measured  and  it  was  found 
that  the  mean  spore-length  of  most  of  the  strains,  when  grown  on  green  bean  pods, 
is  15  microns.  Other  strains  were  found,  however,  which  have  a  mean  spore-length 
of  12  and  17  microns  respectively. 

The  cultures  can  be  classified  according  to  their  mycelial  characters,  when  grown 
on  artificial  media.    Class  A.  Mycelium  dark,  olive  color,  giving  a  fluffy  growth  with 
but  scant  spore  production.    Class  B.  Mycelium  dark,  appressed  but  abundant 
spore  production.    Class  C.  .White  mycelium  and  abundant  spore  production. 
Sexuality  in  Cunninghamella.    O.  F.  Burger 

Pure  cultures  were  made  from  single  spore  heads  of  Cunninghamella  hertholletia 
and  during  the  entire  work  no  zygospores  were  formed  in  the  culture  tubes.  But 
when  two  strains,  whose  gametes  were  compatible  are  contrasted  in  an  agar  plate 
zygospores  are  produced  at  a  point  where  the  cultures  meet. 

A  sexual  reaction  did  not  occur  with  Blakeslee's  Mucor  V,  plus  and  minus,  or 
his  plus  and  minus  strains  of  Cunninghamella  echinulaia.  The  strains  of  C.  her- 
thoUetiae  which  acted  as  neutrals  with  these  two  fungi  formed  normal  zygospores 
when  contrasted  among  themselves. 

The  peculiarity  in  their  method  of  conjugation  is,  that  there  were  marked  differ- 
ences in  their  ability  to  conjugate  with  certain  strains.  Strain  A  will  cnjugate 
with  strains  B  and  C  and  strains  B  and  C  will  also  conjugate  and  form  normal  zy- 
gospores. Cunninghamella  bertholletias  is  therefore  a  pseudo-he terothallic  mucor. 
Curly  (op  of  the  sugar  heel.    Ralph  E.  Smith 

No  abstract. 

One  session  was  devoted  to  a  discussion  of  the  so-called  non-parasitic  or  physio- 
logical plant  diseases,  attention  being  paid  to  a  number  of  obscure  troubles  which 
are  of  particular  importance  in  the  Far  West.  A  discussion  also  took  place  concern- 
ing possible  means  of  making  the  Society  more  useful  and  securing  a  representative 
attendance  from  the  different  states  at  its  meetings.  The  acting  secretary  was  in- 
structed to  take  up  the  latter  subject  with  members  in  the  territory  covered  by  the 
Division  to  see  what  can  be  done  along  this  line. 

W.   T.  HORNE, 

Secretary 'Treasurer 


LITERATURE  ON  AMERICAN  PLANT  DISEASES' 

Compiled  bt  Eunice  R.  Oberlt,  Librarian,  Bureau  op  Plant  Industrt  and 

Florence  P.  Smith,  Assistant 

December,  1916,  to  January,  1917 

Alaska  Afiicultttral  Ezperlmant  Stations.    Plant  diseases.    Alaska  A^r.   Ezpt. 

StS8.  Rpt.  1915:  39-41.     1916. 
Allard,  Harry  Ardell.    A  specific  mosaic  disease  in  Nicotiana  viscosum  dialiiiei 

from  the  mosaic  disease  of  tobacco.    Jour.  Afcr.  Research  7,  no.  11:481-486, 

pi.  35.    December  11,  1916. 
Avema  Sacci,  Rosarlo.    Molostias  cryptoKamicas  do  cafdeiro.    Bol.  Agr.    [Sic 

Paulo)  17,  no.  10:  790-840,  fig.  157-285.    Outubro,  1916. 
Baker,  Carl  Fuller.    Additional  notes  on  Philippine  plant  diseases.    Phil.  Agr. 

and  Forester  6,  no.  3:  73-78.    July,  1916. 
Bancroft,  C.  Keith.    Report  on  the  South  American  leaf  disease  of  the  Para  nil^ 

ber  tree.    Jour.  Bd.  Agr.  Brit.  Guiana  10,  no.  1 :  13-33.    October,  1016. 
Funicladium  macronpcrum;  die  back. 
Boyce,  J.  S.    Pyrnia  of  Cronartium  pyriformc.    Phytopathology  6,  no.  6:  446-447. 

December,  1916. 
On  PinuM  ponder ima. 
Brandes,  E.  W.    Report  of  the  plant  pathologist.    Porto  Rico  Agr.  Expt.  Sta. 

Rpt.  1916:  34  35.     1916. 
Kxperiments  in  the  control  of  a  banana  disease;  miscellaneous  experiments. 
Brooks,  Charles,  and  Cooley,  Jacquelin  Smith.    Temperature  relations  of  apple* 

rot  fungi.    Jour.  Agr.  Research  8,  no.  4:  139-164,  25  fig.,  3  pi.    January  23, 

1917. 
Ckivers,  Arthur  Houston.    .\n  epidemic  of  nist  on  mint.    Mycologia  9|  no.  L:  41- 

42.    Januar>',  1917. 
/'iirntnio  Menthtr  Pcrs. 
Cook,  MeMlle  Thurston,  and  Wilson,  Guy  West.    The  influence  of  the^tannin 

content  of  the  host  plant  on  Endothia  parasitica  and  related  species.     New 

Jomey  Agr.  Fbcpt.  Sta.  Bui.  291.  47  p.     1916. 
Short<T  article  with  same  title  published  in  Bot.  Gas.,   November,  1915. 

Not4*d  in  previous  lif«t. 
Dodge,  Bernard  OgiMe,  and  Adams,  James  Fowler.    Notes  relating  to  the  Gymno- 

nfMirangi.i  on  Myrira  and  (\imptonia.     .Mycologia  9,  no.  1:23-29,  1  fig.,  3  pi. 

Jiiiiuarv.  1017. 


1  I'hM  list  aim*  to  iDclu'l**  tb«  i»u)ilu-atioo«  of  North  an*!  South  Amoriea.  th«  WttI  ladia  Mnadn.  9m4 
laias'ls  rootrol»»l  b>  tho  Uait«ii  8t*tM.  aa<l  mrtielM  by  Amariraa  WTit«n  apitoMiag  in  foralp 

All  author*  art  urg*d  to  rodpcrat*  ia  makinc  iho  liat  i-onpWta  b>  Madiat  thoir  ■tiiaiiitM  wad  bjr 
iBc  rorr«>  tiooaaal  a-l-iitioaa.  ao-i  ••pocialU  h\  ralltai  attoatioa  to  m«ritoriou«  artirlct  pnhliillil 
of  r«cul*'  lournala       ll«i»nBU  or  corT«aioaii«ar«  ahouM  t»«  a*MrMM«i  to  Mmm  E.  R.  Ulicrly,  UbtSffteB. 
HuTMu  of  Plant  In  luairy.  U.  8.  IHpt.  Apir.,  Waahiagtoa.  D.  C. 


1917]  Literature  on  American  Plant  Diseases  153 

Blliott,  John  A.    The  sweet  potato  ''soil  rot''  or  ''pox''  organism.    Science  n.  s. 
U,  no.  1142:7(»-710.    November  17,  1916. 
Cyaiospora  batata  gen.  no  v.,  sp.  nov. 
Fawcett,  George  L.    A  Porto  Rican  disease  of  bananas.    Porto  Hioo  Agr.  Expt. 
Sta.  Rpt.  1916:  36^1.    1916. 
Closely  resembles  Panama  disease. 
Fawcett,  Howard  S.    Citrus  scab.    Phytopathology  6,  no.  6:  442-445.    December, 
1916. 
Discussion  of  article  by  Grossenbacher. 

A  Pythiacystis  on  avocado  trees.  Phytopathology  6,  no.  6:  433-435.  De- 
cember, 1916. 

Fromme,  Fred  Denton,  and  Thomas,  H.  E.    The  root-rot  disease  of  the  apple  in 
Virginia.    Science  n.  s.  46,  no.  1152:  93.    January  26,  1917. 
Xylaria  sp. 

Germano  de  Souza,  Raul.  O  Tylenchus  acuto-acudatus  ('i )  nos  cafezaes  de  Indaia- 
tuba.    Bol.  Agr.  [Sfto  Paulo]  17,  no.  9:  726-736,  7  fig.    Setembro,  1916. 

Gile,  Philip  Lindsey.  Chlorosis  *of  pineapples  induced  by  manganese  and  car- 
bonate of  lime.    Science  n.  s.  44,  no.  1146:  855-857.    December  15,  1916. 

Gfissow,  Hans  Theodor.  Canada's  white  pine  possessions  are  threatened  with  ex- 
termination. An  authoritative  discussion  of  whit«  pine  blister  rust.  Canad. 
Forestry  Jour.    18,  no.  1 :  900-906,  illus.    January,  1917. 

Leaf  roll  in  tomatoes?    Phytopathology  6,  no.  6:447.    December,  1916. 

Hartley,  Carl,  and  Pierce,  Roy  Gifford.    The  control  of  damping-off  of  coniferous 

seedlings.    U.  S.  Dept.  Agr.  Bui.  453,  32  p.,  1  fig.,  2  pi.    1917. 

Pythium  debaryanum;  Fusarium  monxliforme;  Corticium  vagum  var,  Solani. 
Heald,  Frederick  De  Forest.    Some  new  facts  concerning  wheat  smut.    Proc. 

Washington  State  Grain  Growers,  Shippers  and  Millers  Assoc.  10th  Ann.  Meet- 
ing, 1916:  38-45,  2  fig.    1916. 
Huard,  Victor  Am6d6e.    Les  principales  espdces  d'insectes  nuisibles  et  de  maladies 

v^g^tales.    [Quebec  Dept.  Agr.]  Bui.  23,  75  p.,  78  fig.    1916. 
Hubert,  Ernest  B.    Celluloid  cylinders  for  inoculation  chambers.    Phytopathology 

6,  no.  6:  447-450,  1  fig.    December,  1916. 
Jehle,  Robert  Andrew.    Means  of  identifying  citrus  canker.    Quart.  Bui.  State 

Plant  Bd.  Florida  1,  no.  1:  2-10,  12  pi.  (partly  col.).    October,  1916. 
Johnson,  James.    Enfermedades  del  tabaco  y  manera  de  combatirlas.    Parte  V. 

Hacienda  12,  no.  4:  124-126,  illus.    Enero,  1917. 
Johnston,  John  Robert.    Enfermedad  de  la  raiz  de  la  cafia  de  azticar.    Hacienda 

12,  no.  4: 117-118,  iUus.    Enero,  1917. 
To  be  continued. 

Marasmius  on  sugar  cane.    Mycologia  8,  no.  2:  115.    March,  1916. 

Comparison  of  M.  stenophyllus  and  M.  8<icchari. 

Lewis,  A.  C.    Cotton  wilt  in  Georgia.    Georgia  State  Bd.  Ent.  Bui.  40,   18  p.,  8 

pi.    1915. 
Varieties  of  wilt  resistant  cotton,  p.  8  ff. 
McClintock,  James  A.    Is  cucumber  mosaic  carried  by  seed'i     Science  n.  s.  44,  no. 

1144:786-787.    December  1,  1916. 

Peanut  mosaic.    Science  n.  s.  46,  no.  1150:  47-48.    January  12,  1917. 

Sclerotinia  libertiana  on  snap  beans.    Phytopathology  6,  no.  6:  436-441, 

2  fig.    December,  1916. 

McCobbin,  W.  A.  The  white  pine  blister  rust:  does  the  fungus  winter  on  the  cur- 
rant?   Science  n.  s.  46,  no.  1152:  87.    January  26,  1917. 


154  Phytopatholoot  [Voi-  7 

Martin,  WillUm  H.    Influence  of  Bordeaux  mixture  on  the  rates  of  trampirmtion 
from  abeciflcd  leaves  and  from  potted  plants.    Jour.  Agr.  Research  7,  no    12: 
52^-548.     December  18,  1916. 
Literature  cited,  p.  547-548. 
Maatey,  L.  M.    The  hard  rot  disease  of  gladiolus.    New  York  Cornell  Agr.  Expi, 
Sta.  Bui.  380:  149-181,  flg.  38-14,  pi.  15^16.     1916. 
Bibliography,  p.  180-181. 
StpUnia  Gladioli, 
Mandlola,  Nemeslo,  and  Bspino,  Rafael  B.    Some  phycomycetous  diaeaaea  of  cul- 
tivated plants  in  the  Philippines.    Phil.  Agr.  and  Forester.  I,  no.  3:  65-71, 
illus.    July.  1916. 
Bibliography,  p.  71. 

Phytophthora  diseases;  Pythium  Ekbaryanum. 
Mix,  A.  J.    Cork,  drouth  spot  and  related  diseases  of  the  apple.    New  York  State 
Agr.  Expt.  Sta.  Bui.  426:  473-522,  12  pi.     1916. 

Nonparasitic. 
'        Sun-scald  of  fruit  trees,  a  type  of  winter  injury.     New  York  Cornell  A^. 
Expt.  Sta.  Bui.  382:  233-284,  fig.  60^1,  pi.  18-19.     1916. 
Literature  cited,  p.  283-284. 

Probably  a  winter  injury  caused  by  direct  freesing  to  death  of  the  tiaaue. 
Morse,  Warner  Jackson.    Studies  upon  the  blackleg  disease  of  the  potato,  with 
special  reference  to  the  relationship  of  the  causal  organisms.    Jour.  Agr.  Re- 
search 8,  no.  3:  79-126.     January  15,  1917. 
Literature  cited,  p.  124-126. 
Hanllu*  atronepticun  Van  Hall. 
Nowell,  William.    Fungoid  and  bacterial  diseases.    West  Indian  Bui.  If,  no.  2: 
133-143,  146  147.     1915. 
Listed  under  host  and  locality. 
See  also  p.  121-122. 
Fungous  and  bacterial  diMoases.     West  Indian  Bui.  16,  no.  1:  17-25, 


1916. 

Listed  under  host  and  locality. 
See  also  p.  2. 

Hosellinia  root  diMMifles  in  the  I^esser  .Antilles.     West  Indian  Bui.  li,  no. 

1:31  71.  12  fig.  on  4  pi.     1916. 
Keferenc«»H,  p.  (H)  71. 
Orton,  Clayton  Roberts.     Phytophthora  infestans  on  tomatoes  in  .\ustralia.     Phy- 
topathology 6,  no.  6:  447.     Drci'mln^r,  1916. 
Osner,  George  A.     I^>af  smut  of  timothy.     New  York  Cornell  Agr.  Kxpt.  Sta.  BuL 
,3S!:  is:>  230,  fig.  4:>  .W,  pi.  17.     1916. 
Bihli«»graphy,  p.  22«'>  2.10. 
f '  •» / 1  higii  ntritrform  if . 
Paul,  B.  H.    Th«*  pine  blinUT  niMt.     (\»nwrv.  Com.  State  New  York  BuL  15,  18  p., 

illiiM..  1  foM   map.     [1917.1 
Seaver,  Fred  Jay.    Sonu*  p:i|N>rH  pn>(M*iit4;d  during  convocation  week.     Mycolofpa 
9,  no,  1:42  -U*.     Jaiiuiiry.  1917. 

Joint  fW'Minii  of  Hot.  Sor.  an<l  Phytopath.  Soc,  P>iday,  I>ecember  28,  1916, 
in  connection  with  .\nirr.  .\.Hf«i)c.  .\dv.  S4m. 
Smith,  Erwln  Frink.     .Mrrhani^ni  of  tumor  growth  in  crowngall.     Jour.  Agr.  He- 
m-arch 8,  no.  r»:  1(W>  1S(>.  pi.  4  <m.     January  29,  1917. 
Literature  cited,  p.  is^lW. 

|PnYTOPATHoi/)<iV,  foF  Fehruafv,  1917  (7:  \~M,  PI.  I)  wan  iiisued  Fob- 
nmr\'  7,  HUT. I 


PHYTOPATHOLOGY 

VOLUME  VII  NUMBER  3 

JUNE,  1917 


STUDIES  ON  BACTERIUM   SOLANACEARUM' 

E.    E.    Stanford   and   F.   A.    Wolf 
With  One  Figure  in  the  Text 

Studies  on  the  wilt  diseases  caused  by  Bad,  solanacearum  have  been 
in  progress  at  the  North  Carolina  Agricultural  Experiment  Station  since 
1903.  A  recent  bulletin  (4)  dealing  primarily  with  remedial  and  pallia- 
tive measures  for  tobacco  wilt  contains  the  results  of  certain  of  these  in- 
vestigations. In  the  present  paper  are  presented  data  bearing  (1)  on 
the  distribution  withiil  North  Carolina  of  the  disease  on  tobacco  {Nicotiana 
iabacum)  and  tomato  (Lycopersicon  escuUntum),  (2)  on  cultural  studies 
to  determine  the  identity  of  the  strains  from  the  several  hosts  and  (3) 
on  the  results  of  cross  inoculations. 

distribution   of   BACT.    solanacearum   within   north   CAROLINA 

Tobacco  wilt  has  probably  been  present  within  the  state  for  at  east 
twenty-five  years,  but  occurs  in  only  a  small  proportion  of  the  lands  de- 
voted to  tobacco  culture.  The  disease  was  first  definitely  recognized 
in  the  southern  portion  of  Granville  county  in  1902.  Records  indicate 
that  the  disease  has  yearly  continued  to  spread  so  that  it  now  occurs  in 
eleven  counties,  namely:  Granville,  Durham,  Vance,  Wake,  Franklin, 
Ashe,  Guilford,  Greene,  Davidson,  Chatham  and  Yadkin. 

The  losses  in  the  first  four  of  these  counties  are  confined  to  the  southern 
portions  of  Granville  and  Vance  and  the  northern  portions  of  the  adjacent 
counties  of  Durham  and  Wake.  In  this  area  the  disease  is  so  generally 
destructive  that  the  growing  of  tobacco  has  been  abandoned  on  many 
farms.  The  disease  is  confined,  however,  to  relatively  small  areas  in 
the  seven  remaining  counties. 

*  Acknowledgment  is  hereby  made  to  the  several  members  of  the  Department 
of  Botany  and  Plant  Pathology  of  North  Carolina  Agricultural  College  and  Experi- 
ment Station,  who,  since  the  inception  of  these  investigations,  have  aided  in  the 
work. 


1S6  Phytopatholooy  [Vou  7 

It  is  tt  striking  fart  that  collections  of  Imcterial  wilt  of  tomato  which 
have  been  vcr>'  Rcncrally  made  throughout  the  State  show  that  the  diaeaap 
on  tomatoes  orcura  in  thirty-nine  counties  of  the  state.  It  is  realised, 
of  course,  that  the  disease  on  Itoth  tobacco  and  tomat^x^  may  not  have 
been  reported  from  all  localities  in  which  it  may  occur,  yet  the  fact  remsiiu 
that  the  disease  on  the  two  host«  is  not  coextensive.    No  a<lequatc  exfdana- 


Piii.   1.  Map  op  North  Caholika  Shiiwino  the  Known  Dihtubltion  or 

BArTERIVM    HOLASArEAKl'H    ON"    ToSACCO   ASO-OS   ToMATO  ' 

tion  is  ut  hnnd  (o  iiccount  for  this,  in  xiew  of  the  fact  that  reriproeal  inoni- 
latioat  nre  ho  caHJiy  i-fTocted  and  that  the  strains  of  Bad.  iioiaTiactarum 
from  IiiIhicco  and  toniattx-s  arv.  identical  as  shown  by  the  cultural  atudim 
of  scvend  investifiiitorx  and  ronfimwd  by  studies  to  l»e  presented  later 
in  this  [uipiT. 

It  nuKht  Ik>  ad<lc<l,  that  no  <luta  have  accumulat^l  relative  to  the  di»- 
tribulitm  of  tliis  purHHite  on  otht-r  solanat-eous  hotts  and  that  the  tliseaa» 
on  peanut  (ATtickin  hypog(ra)  has  Ixfn  ol>serve<l  in  one  locality  only. 

nXTIHAL   HTrniES 

In  view  of  the  fact  that  in  wrtain  sections.  Bad.  Kilanacearum  ts  not 
present  on  ull  of  the  hosln  which  un-  known  to  l>e  subject  to  attack,  a  aludy 
by  means  of  artiliml  cultun-s  w:is  nmde  to  iletermine  the  identity  of 
the  stniinK  from  the  more  comnKin  hosts.  Several  investigatots,  anioiiK 
wbnni  iii:iy  Is-  nientionetl  Smith  ( '>  an<l  0)  and  Honing  (6)'  have  ptvnouiJy 
r(']M>rlvd  cxU'iiMve  .stu<li<-s  on  Hact.  solaniteearum  in  artificial  culture  and 
n-giinl  t) rgHniMii  from  (be  s«'viTid  hosts  as  identical.     Nevcrthplesn. 

t  Hi-ri-n-nri-H  III  rill-  imMii'iiliiniH  of  lloninii.  HunK<-r.  und  I'yrdk  mi*  given  in  Vol* 
uiiK-  :l  'if  .><iiiil>i'i'  tlrK'iirin  in  Hi-liilion  to  I'tiinl  Diwhwh.  Tho  tulhora  haw  not 
■rfii  l)ir>>^  i>iililii'Bti»iii>.  I>iil  only  ilii'  alMtnirtH  lavrti  \>y  I>r.  Smith.  BiMiocr«phitw 
of  Hart.   ...^l.,.l,■■.,r..n.  on  p.  -.'Is  iWi  iind  1*70-271. 


1917]  Stanford  and  Wolf:  Bacterium  solanacearum  167 

parallel  cultures  of  the  organism  isolated  from  tobacco,  potato,  (Solanum 
tuberosum)  tomato,  eggplant  (Solanum  mslongena),  peanut,  ragweed 
{Ambrosia  artemisiifolia)  and  Edipta  alba  have  been  made.  These  isola- 
tions were  made  from  various  parts  of  the  hosts  and  from  plants  from  several 
localities  within  the  state.  In  general,  the  cultural  variations  which 
appeared  between  the  strains  from  the  different  hosts  were  no  greater 
than  those  from  strains  all  of  which  came  from  the  same  host.  Since, 
however,  certain  additional  facts  are  brought  to  light,  a  brief  account 
of  the  growth  in  culture  is  pertinent  and  is  herewith  given. 

Colonies  on  agar  plates  usually  become  visible  within  thirty-six  to  forty- 
eight  hours  at  28°C.  At  a  temperature  4  to  5°  lower,  they  may  be  scarcely 
noticeable  at  the  end  of  seventy-two  hours.  They  are  at  first  white, 
wet-shining  and  opalescent,  circular  in  outline,  slightly  raised  and  with 
smooth  margin.  Colonies  become  3  to  5  mm.  in  diameter  in  five  to  six 
days.  They  soon  become  distinctly  opalescent-blue  by  transmitted  light, 
when  the  plates  are  held  some  distance  from  a  poorly  Ughted  reflecting 
surface.  When  the  colonies  are  viewed  with  the  blue  sky  for  a  back- 
ground, they  are  distinctly  brown  with  faint  concentric  rings.  Later, 
they  become  very  markedly  brown  by  reflected  light.  The  pigmentation 
originates  at  the  center  of  the  colony,  spreads  toward  the  margin  and  is 
diffused  somewhat  into  the  agar.  The  color  is  more  intense  at  the  cen- 
ter of  the  colony.  Subsurface  colonies  are  globose  or  lenticular,  much 
smaller  than  the  surface  colonies  and  become  brown  much  sooner  than 
do  the  surface  colonies. 

The  growth  on  agar  slants  develops  slowly,  is  filiform  at  first  and  usually 
spreading  at  the  bottom  of  the  slant.  It  is  shghtly  elevated  and  the  mar- 
IB^  is  entire  or  wavy.  Colors  and  pigmentation  develop  similar  to  those 
in  plate  colonies  with  considerable  variation  in  time  of  appearance  and 
intensity  of  pigmentation  which  may  vary  from  scarcely  perceptible  to 
brownish  black.  When  Witte's  peptone  is  used,  a  deeper  pigmentation 
develops  than  when  Difco  peptone  is  employed.  When  the  colonies 
become  blackened,  the  organism  is  no  longer  viable.  It  appears  to  re-  | 
tain  its  vitaUty  for  about  four  and  one-half  months  on  agar  but  rapidly ' 
loses  its  virulence  on  this  medium. 

The  appearance  of  colonies  on  Utmus  lactose  agar  slants  is  similar  to 
those  on  nutrient  agar.  The  Utmus  is  at  length  sUghtly  reduced.  Pig- 
mentation is  first  noticeable  in  three  to  four  weeks  and  a  brown  stain  soon 
becomes  diffused  throughout  the  agar  and  masks  its  color.  Portions  of 
the  substratiun  which  are  not  brown  become  sky-blue  by  diffuse  Ught 
and  reddish  plum-colored  by  transmitted  Ught. 

The  appearance  of  this  organism  in  bouillon  cultures  is  somewhat 
variable.    A  rather  uniform  clouding  develops  within  twenty-four  hours 


158  PHYTOPATHOLOCiY  (VoL.  7 

which  l)erome8  so  intenflely  opaque  within  a  week  as  to  make  it  impo»- 
nihle  to  see  through  a  l)Ouillon  tulx;  when  the  tul)e  is  placed  immeclistely 
in  front  of  an  object.  Numerous  pseudogloeae  may  appear  forming 
flocculent  particles  on  the  surface.  No  pellicle  nor  ring  is  formed,  but 
a  thin,  opalescent  scum  appears  on  the  surface.  A  dirty  white,  viMom 
precipitate  develops  within  a  week  or  two.  Within  four  to  six  weeks, 
this  precipitate  will  have  l)ecome  dense  and  the  supernatant  l)ouiIlon 
will  have  liecome  cl(»ar  at  which  time  the  organism  Ls  no  longer  \'iable. 
Various  degrees  of  pigmentation  may  occur,  l>eing  more  intense  with 
Witte's  than  with  Difco  peptone.  Tul)es  of  the  l>ouillon  made  with  the 
fonner  l>ecome  hn)wnish  black  on  long  standing. 

(>n  potato  plugs,  the  growth  is  spreading,  thin  or  slightly  raised,  white 
or  flc^sh-i'olorefl  at  first  l)Ut  rapidly  In^comes  bn)wn,  often  pitch-black. 
The  surrounding  licjuid  U'coines  clouded  and  bn)wn.  The  organism  is 
short -live<l  on  this  n)edium  and  conuiionly  loses  its  vitality  within  a 
wec»k.  The  vinil(»n<'e  of  linct.  siflanaccfirum  on  artificial  me<lia  is  liest 
retained  on  |X)tat()  phigs.  but  transfers  must  Ik*  made  at  inter\'als  of  aliout 
two  davs. 

When  gn)wn  on  milk,  there  is  no  peptonization  nor  precipitation  of 
ca.«ein.  A  slight  visci<lity  and  the  odor  of  putn»faction  are  developed 
and  the  medium  at  length  In^comes  bn>wn  and  alkaline. 

The  organism  (*auses  n  partial  clarification  of  litmus  milk  with  a  ck^p- 
ening  of  th<»  blur  color  which  apfx^ars  n*ddLsh  by  transmitted  light.  A 
slight  dirty  white  i)n»cipitate  is  fonned,  which  lK»(*i>mes  brown  on  loiiK 
standing.     The  ba<*teria  may  n»main  viable*  for  five  months  on  this  me<lium. 

The  surface  coloni<»s  on  gelatin  are  small,  circular,  white  and  wet-shin- 
ing. Submerge<i  colonies  an*  glolMist*  and  yellowi.sh  to  brownish,  (irowth 
aU»ng  the  line  of  the  stab  on  gelatin  is  white,  later  l)ecoming  bn)wn,  fila- 
mentous and  lH*st  at  the  surfacr  of  the  medium.     No  liquefaction  cMM'urK. 

TIm'H*  is  no  evident  gn)wth  on  Crohn's  .solution  in  four  weeks.  C>n 
I'schinsky's  soluti<»n,  growth  ranges  fnun  none  to  feeble  with  slight 
clouding. 

Ill  (lrxtn>s«»  bn»th.  a  copious  gn»wth  develops  in  the  opi»n  arm,  extc^nd- 
ing  (»iily  to  thr  bas4'  of  the*  <*Ios4mI  ann.  .\n  abundant,  rather  viseoiis 
|)rf('if)itatr  ap|M>ars.  Th<>  nHMlium  at  Irngtii  lK*comc*s  bn)wn  in  the  o\H*n 
ann  and  i^  strongly  alkalinr  with  no  evolution  of  gits. 

<  ultural  <*harartrrs  on  s;i<*charos<*  bn>th  an*  similar  to  those*  on  tlextrnwe 
with  a  l«»s>  marked  tend«*nrv  to  the  development  of  a  bmwn  color. 

(Irn\%th  i*«  fe<*ble  on  la<ioM*  brcith  with  little  .s<m I i mentation  and  little 
or  ni»  bniwii  eolur  i?^  devel<»|MMl,  even  after  s<»ven  w<»<»ks.  The  acidity  of 
aril!  broth  is  dimiiiishe<{  l>ut  neutral  broths  an*  not  rendered  alkalin. 
<>n  niannit.  the  growth  eharaeters  an*  similar  to  thos4»  on  lactos<\     .\  ver>* 


1917]  Stanford  and  Wolf:  Bacterium  solanacearum  159 

copious  growth  ensues  in  glycerin  broth  with  a  marked  development  of 
brown  color.  Growth  on  maltose  is  similar  to  that  on  dextrose.  Nitrates 
and  ammonia  are  formed  in  moderate  amount  in  nitrate  solutions. 

Growth  is  much  delayed  and  diminished  in  hydrochloric  acid  +25 
Fuller's  scale,  and  is  entirely  inhibited  at  +30.  No  growth  occurs  in 
double  strength  bouillon  rendered  +33  acid  by  the  addition  of  expressed 
tomato  fruit  juice.  Smith  (6)  reports  growth  in  +33  acid  of  beef  juice. 
The  optimiun  reaction  lies  between  +10  and  +15.  ^ 

Growth  is  slight  or  none  in  bouillon  --5  with  sodium  hydroxid.  No 
growth  occurred  in  —10  sodium  hydroxid.  The  organism  is  little  re- 
tentive of  vitality  on  culture  media.  Milk  appears  to  be  the  best  medium 
for  long  continued  growth  on  Bad,  solanacearum.  The  organism  may 
remain  viable  for  two  months  in  sterilized  distilled  water.  No  evidence 
of  diastatic  activity  was  found  when  the  organism  was  grown  on  potato 
plugs. 

A  considerable  number  of  special  media  have  been  prepared,  among 
which  are  soil  extract,  casein  agar,  Hey  den's  Nahrstoff  agar,  potato  agar, 
potato  leaf  agar,  and  tomato  leaf  agar.  No  growth  of  diagnostic  signifi- 
cance developed  on  any  of  these  media. 

Bacterium  solanacearum  is  very  short-lived  in  mixed  cultures.  Honing 
(6)  noted  a  marked  antibiosis  between  the  wilt  organism  and  B.  mesen- 
tericus  as  well  as  other  species  plated  from  wilted  tobacco.  In  our  studies 
also,  various  bacteria  have  been  found  to  replace  Bad,  solanacearum  in 
decaying,  wilted  plants.  Five  strains  of  yellow  chromogens  isolated 
from  diseased  tomatoes,  tobacco  and  peanuts  were  found  in  the  fall  of 
1915  to  exhibit  marked  antagonism  to  the  wilt  organism.  In  inter- 
secting streaks  on  agar  plates,  the  chromogens  tended  to  crowd  out  the 
parasite.  The  presence  of  B,  mesentericus  and  other  soil  inhabitants 
appear  never  to  be  so  antagonistic,  however,  as  to  eliminate  Bad,  solanace- 
arum from  infested  soils. 

Thus  far  attempts  to  isolate  the  parasite  directly  from  infested  soils 
have  been  unsuccessful.  This  is  due  in  part  at  least  to  the  fact  that 
Bad,  solanacearum  is  inhibited  by  other  soil  inhabitants  which  develop 
on  the  plates.  Honing  (6)  however,  succeeded  in  isolating  it  on  plates 
from  dilution  cultures  of  well  water. 

cross-inoculation  experiments 

Bacterium  solanacearum  has  previously  been  shown  to  attack  mem- 
bers of  eight  widely  separated  families,  Urticacese,  Leguminosae,  Tropaeo- 
lacese,  Euphorbiaeeae,  Verbenaceae,  Solanaceae,  PedeUaceae  and  Compositse. 

The  organism  was  first  described  by  Erwin  F.  Smith  (5)  in  1896  as 


160  Phytopathology  [Vol,  7 

the  cauae  of  a  wilt  disease  of  tomato,  eggplant  and  potato  and  he  succesa- 
fully  inoculated  Solanum  nigrum,  Datura  stramonium,  D.  mdelUndeM, 
D.  foMuosa,  D,  cornucopia^  Physalis  crasnfolia,  P.  philaddphiea  and 
Petunia  (hybiid). 

Several  investigators,  among  whom  are  Hunger  (6),  Stevens  and  Sackett 
(7)  and  Uyeda  (6)  have  reported  a  wilt  disease  of  tobacco.  Honing  (6) 
in  1910  first  reported  this  organism  as  the  cause  of  disease  in  plants  out- 
side of  the  fk)lanacea*.  He  found  it  in  Pouzolzia  sp.,  Phyaalia  angulata^ 
Indigofera  arreeta,  Arachis  hypogceOy  Mucuna  sp.,  Acalypha  boehmeroideM^ 
Ageratum  conywides,  SpUanthes  acmella,  Pluchea  indica,  Blumea  baUami' 
fera,  Synedrella  nodiflora  and  Tectona  grandia.  He  also  successfully  inocu- 
lated several  ornamental  varieties  of  Nicotiana,  Capsicum  annuum  and 
Sesamum  orientate, 

A  wilt  disease  upon  peanut  was  sul)sequently  reported  from  North 
Carolina  (2)  and  later  studies  (3)  in  this  state  added  two  composites. 
Ambrosia  artemisiifolia  and  Eclipta  altni,  to  the  list  of  naturally  infected 
hosts. 

A  wilt  of  nasturtium  (Tropetolum  maju^)  caused  by  Bad.  sotanacearum 
was  reported  from  Maryland  by  Br>'an  (1).  She  succeeded  in  inoculating 
also  the  common  cultivated  Agc^ratum  and  Verbena. 

The  artificial  inoculation  ex|x^riments  conducted  at  the  North  Carolina 
Kxperinu*nt  Station  prior  to  1913  were  confined  primarily  to  solanaceous 
plants.  When  in  the  summer  of  1912,  it  was  found  that  peanuts  are 
subject  to  attack  by  Bact,  solanacearum,  this  host  was  successfully  inocu- 
lated with  strains  fn>m  tobacco,  peppers  and  peanuts.  The  strains  from 
peanuts  wen*  also  found  to  l)e  pathogenic  to  tobacco. 

During  the  season  of  1914,  Bact.  solanacearum  was  isolated  from  di»> 
ease<l  ragi)^'ee<ls  (Ambrosia  artemisiifolia)  and  subsequently  found  to  be 
prcKluctive  of  wilt  on  tobacco,  tomato,  potato,  Eclipta  alba  and  ganlen 
nasturtium  (TropuK^lum).  The  recipr(H*aI  inoculations  upon  ragweed 
with  strains  fn>m  tobacco,  tomato,  potato  and  Eclipta  aU>a  were  rather 
unsucc(*ssful.  No  systemic  invasion  n^sulting  in  death,  but  merely  a 
local  o<*clusion  and  blackening  of  xyl<»m  elements  occurred  in  inoculated 
plants. 

In  tin*  fall  of  1915,  strains  isolatiNi  from  wilted  Eclipta  atba  were  auc- 
c(*Ksfully  inocuhit<'<l  into  tomatoes,  potatoes,  tobacco,  garden  nasturtiunui 
and  Eclipta  allnt,  A  nit  her  more  comprehensive  series  of  inoculations 
on  rultivatcd  an<i  wild  s|)4*cies  was  in.stitut4*d  in  191G,  the  results  of  which 
an»  hcn»in  brit^Hv  sum!nanze<l. 

Mrthtti  of  vHticultittifU.  The  strain  of  Bact.  yolatmcearum  emplo^Td  in 
niakiiig  the  initial  inixulations  wa.s  (»btaincd  by  the  pounxl  plate  method, 
fnim  wilted  t4>barro  plants  from  Cn'^Mlmoor.  North  Carolina.     As  sooo 


1917]  Stanford  and  Wolf:  Bacterium  solanacearum  161 

as  the  organism  had  developed  on  these  poured  plates,  transfers  were 
made  to  potato  plugs.  Rep)eated  transfers  at  intervals  of  one  to  three 
days  were  made  on  this  medium.  The  pigmentation  on  old  cultures  on 
agar  and  on  potato  plugs  was  regarded  as  sufficiently  characteristic  to 
estabhsh  the  identity  of  the  wilt  organism.  Inoculum  from  one-  to  three- 
days-old  cultures  on  potato  plugs  was  used  in  all  of  the  inoculations. 
Inoculations  were  made  by  pricking  the  plants  near  the  tips  of  the  branches 
and  inserting  the  inoculum.  A  niunber  of  check  plants,  either  iminjured 
or  pricked  with  a  sterilized  needle  were  used  in  the  case  of  each  species 
tested.  Since  it  was  known  that  Bad.  solancLcearum  loses  its  virulence 
even  though  repeated  transfers  are  made,  no  attempt  was  made  to  use 
the  original  strain  from  tobacco  in  all  of  the  inoculations.  Instead,  isola- 
tions from  certain  of  the  inoculated  species  were  used  in  continuing  the 
series  of  inoculations.  Some  differences  in  virulence  appeared  in  strains 
which  had  passed  through  different  hosts  but  no  such  marked  decrease 
occurred  as  when  the  organism  is  repeatedly  transferred  on  culture  media. 

In  general,  young,  vigorously  growing  plants  were  used  in  these  tests, 
although  in  some  cases,  rather  matiu*e  plants  were  employed.  The  cul- 
tivated species  were  grown  either  in  the  greenhouse  or  in  small  experi- 
mental plats  at  West  Raleigh,  North  Carolina  and  the  weeds  grew  in 
waste  places  where  they  could  be  kept  under  observation  for  the  neces- 
sary length  of  time.  In  general,  as  soon  as  inoculated  plants  showed 
s3anptoms  of  disease,  they  were  examined  microscopicaUy  to  determine 
the  presence  of  bacteria  within  the  tissues  at  points  remote  from  the  point 
of  inoculation.  The  organism  was  then  reisolated  by  the  poured  plate 
method,  and  its  identity  established  by  the  characteristic  growth  on  agar 
and  potato  plugs.  As  supplementary  evidence,  the  reisolated  organism- 
was  inoculated  into  tomatoes  or  tobacco. 

The  accompanying  diagram  of  the  plan  of  these  cross-inoculation  experi- 
ments has  been  so  arranged  as  to  show  at  once  the  source  of  the  inoculum, 
the  result  of  the  inoculation  and  the  number  of  plants  inoculated. 

ResuUs.  When  comparison  is  made  with  the  host  species  previously 
enumerated,  it  will  be  seen  from  this  tabulation  of  the  results  of  cross 
inoculations  that  the  following  plants 'have  heretofore  been  unreported 
as  subject  to  attack  by  Bad,  solanacearum:  Stizolobium  niveum,  Tropceo- 
lum  lobbianumy  T,  peregrinum,  Croton  glandulosus  var.  s&ptentrionalia, 
Impatiens  batsamina,  Verbena  erinoides,  Lycopersicon  cerasiforme,  L. 
pyriformey  Browallia  demissa,  Physalis  alkekengij  Schizanthus  pinnatus, 
Salpiglossis  sinuaia  and  Martynia  proboscidea.  Twelve  of  these  species 
belong  to  families  representatives  of  which  had  hitherto  been  known  to 
be  subject  to  attack  and  one  species,  Impaiiens  balsaminay  belongs  to 
an  additional  family. 


162  PinTOPATHOLOOY  [VoL.  7 

I  "-si* 

"■     B     ■•    • 

?  3  S  J 


i  7 


--5  5 

,  Jil: 

3  «  t  :  p  I  i 

2  S^  5  •   k  ? 

i  J  «c  -    fc    "    1 


P  ^ 


!.mj 


1917]  Stanford  and  Wolf:  Bacterium  solanacearum  163 

It  may  also  be  noted  from  the  tabulation  that  no  infection  resulted  in 
Stizolobium  niveum  and  Physalis  alkekengi  when  inoculated  with  the  or- 
ganism isolated  from  wilted  Impatiens  balsamina.  Further,  no  demon- 
strable infection  resulted  in  the  case  of  Petunia  (hybrid),  Datura  cornu- 
copia,  D,  fastv4)8a,  and  Physalis  alkekengi  when  the  isolations  were  made 
from  wilted  Browallia  demissa.  Smith  (6)  had  previously  shown  the 
first  three  of  these  forms  to  be  subject  to  attack.  Since  Stizolobium  niveum 
wilted  when  Datura  tatula  was  the  source  of  the  inoculum  and  Physalis 
alkekengi,  when  wilted  Verbena  erinoides  was  employed,  it  is  indicated 
that  virulence  is  influenced  by  the  host  plant. 

In  the  following  species,  Uttle  or  no  external  injury  resulted  from  inocu- 
lation, but  the  vascular  tissues  were  found  to  be  invaded:  Euphorbia 
nutans,  Solanum  carolinense,  Physalis  angulata,  Impatiens  sultani,  Bid^is 
bipinnata  and  Erigeron  canadensis. 

Inoculated  plants  of  Ambrosia  artemisiifolia  and  Eclipta  alba  wilted 
thus  confirming  previous  studies  (3). 

In  general,  it  can  be  said  that  the  external  symptoms  and  pathologi- 
cal histology  of  the  plants  which  were  artificially  inoculated  in  these  studies 
differed  in  no  essential  particular  from  those  of  other  species  which  have 
previously  been  reported  as  hosts  for  Bact.  solanacearum.  The  8p)ecies 
of  Tropseolum,  Lycopersicon,  BrowalUa  and  Eclipta  tested  are  to  be 
regarded  as  very  susceptible,  whereas,  Stizolobium  niveum  and  Physalis 
alkekengi  appear  to  be  very  resistant.  That  Stizolobium  niveum  is  highly 
resistant  is  shown  by  the  fact  that  in  a  field  test  at  Creedmoor,  North 
Carolina,  no  demonstrable  infection  develop)ed  in  any  of  the  plants  grown 
in  wilt-infested  soil.  It  is  interesting  to  note  that  when  young  ragweed 
plants  grown  in  the  greenhouse  were  inoculated,  they  quickly  succumbed 
to  wilt,  while  numerous  individuals  grown  out  of  doors  when  inoculated 
with  the  same  strain  showed  no  external  symptoms  of  disease.  Little 
external  evidence  of  disease  developed  in  rather  mature  plants  of  Croton 
but  young  plants  were  easily  wilted.  In  the  case  of  Impatiens  balsamina, 
the  foliage  became  slightly  wilted,  some  distortion  of  the  stems  occurred 
and  adventitious  roots  were  formed.  The  discoloration  of  the  vasculaV 
bundles  of  the  stems  showed  through  the  cortical  tissues  as  brown  streaks. 
This  species  was  found  to  wilt  slowly  when  inoculation  was  effected  by 
potting  plants  in  infested  soil.  The  discoloration  of  the  vascular  system 
is  externally  visible  in  wilted  stems  of  Eclipta  alba  and  the  leaves  become 
characteristically  crisp  and  blackened. 

The  economic  bearing  of  these  additional  weed  and  cultivated  host 
plants  for  Bact.  solanacearum  upon  the  problem  of  wilt  control  is  at  once 
apparent  when  it  is  indicated  that  certain  of  these  forms,  namely;  Erigeron 
canadensis,  Ambrosia  artemisiifolia.  Euphorbia  nutans,  Croton  glandulosus. 


164  Phytopathology  [Vol.  7 

and  Solanum  carolinense  are  widespread  in  cultivated  fields  in  the  State. 
Edipta  alba  is  often  found  in  ill-drained  lands.  Datura  tatuia  and  Bidenti 
bipinnala  are  not  uncommon  weeds  about  farm  buildings  and  lots.  The 
Lycopersicons  and  Martynia  probascidea  are  locally  rather  common  in 
gardens.  The  Tropsolmns,  Verbena,  Impatiens,  Browallia,  Schixanthus, 
Salpiglossis  and  Physali^  alkekengi  are  more  or  less  commonly  grown  as 
ornamental  plants.  The  results  with  velvet  beans  (Stizolobium  niveum) 
which  is  related  to  Mucuna  mentioned  by  Honing  (6)  are  significant 
since  this  crop  is  becoming  of  considerable  importance  in  the  South.  At 
least,  it  cannot  l)o  recommended  that  velvet  l)ean8  Ix"  grown  in  a  rotation 
s\'8tem  in  soils  infested  with  Bad.  aolanacearum. 

SUMMARY 

1.  A  wilt  of  tobacco  caused  bv  Bad,  Holanacearum  has  been  observed 
in  North  Carolina  in  eleven  counties  and  a  tomato  wilt  caused  bv  the 
same  organism  has  U^^^n  noted  in  thirty-nine  counties. 

2.  Pn»viou8  cultural  studies  on  the  idcntitv  of  Bad.  solanacearum  from 
various  hosts  are  (Confirmed  since  the  variations  which  appeare<l  in  the 
strains  from  tobacco,  (Nitato,  tomato,  eggplant,  fx^anut,  ragweed  and 
Ediftta  alba  were  no  gn»atcr  than  in  strains  all  of  which  came  from  the 
same  host. 

3.  A  new  family  of  phanerogams,  Balsaminac(*ip,  has  been  addcnl  tii 
the  nuinlxT  previoiu<ly  reportcil  to  contain  host  six'cic'S  of  Bad.  solana- 
cearum.  MemlM*rs  of  nine  families  arc  now  known  to  Ih'  subject  t4)  attack 
by  this  organism.  Thirt(M*n  additiomil  si>ecies  of  plants,  classifieil  as 
follows  showe<l  wcll-<h'fincd  wilting  or  serious  injur>': 

Ii4*ginHinosa*        Sticolobium  nm^um 

Tn)j)aH)lacea»        Trofxrolum  lobbumum,  T.  lyeregrinum 

Kuphorbiaceu*     Croion  glandulosus  var.  neptenirionali^ 

Balsa  in  ina(*ca>      ImfHitietM  balsamina 

VcrlH*nu<M*a»  \'t'rhi'nn  vrifundeH 

Soluna(M»a»  Lycofpertfmm  crrasiformr,  L.  pyriformr,  Brovnil* 

I  in  (i4'mis8a,   Physalis  alkekengi,  SdiisanlhuJt 
pinnntuii,  Salpiglossis  siniiata 

VriM'iiivviv  .Martynia  prttl}Osci(U'a. 

No  outward  si^n**  of  disease  (|rvcl(»|M  <1  in  the  vnsv  of  six  other  s|M»cie3* 
in  whirh  the  org:uii*<tii  nuiltiplied  rapidly  within  the  vascular  |)ortioas. 
Fivf  4»f  these  sfNMMes  an*  previously  unre|K)rt«'d,  mmicly: 

Kuphorbiacea*      Euphorbia  nutans 

Solaiuieea'  Stdanum  carolimnse 

Hals^iiiiinaeea'      Im/nitiens  sulidini 

( *on  1 1  ¥ »-« i  t  a'  B  idens  bipin  nata ,  Erigeron  ca  tuidensiM. 


1917]  Stanford  and  Wolf:  Bacterium  solanacbarum  165 

literature  cited 

1.  Bryan,  Mary  K.    A    nasturtium    wilt    caused    by    Bacterium   solanacearum. 

Jour.  Agr.  Research  6:  451-157,  pis.  63-64,  figs.  3.     1915. 

2.  Fulton,  H.  R.,  and  Winston,  J.  R.    A  disease  of  the  peanut  caused  by  Bac- 

terium solanacearum.    Nofth  Carolina  Agr.  Exp.  Sta.  Ann.  Rept.  86  and 
87:  4a-47,  figs.  4.     1913-14. 

3.  Fulton,  H.  R.  and  Stanford,  E.  E.    Two  wilt  hosts  of  Bacterium  solanacearum, 

Phytopath.  6:  108.     1916. 

4.  Garner,  W.  W.,  Wolf,  F.  A.,  and  Moss,  E.  G.    Control  of  tobacco  wilt  in  the 

flue-cured  district.    United  States  Bur.  Plant  Ind.  Bui.     (In  press.) 

5.  Smith,  Erwin  F.    A  bacterial  disease  of  the  tomato,  eggplant,  and  Irish  potato, 

(Bacillus  solanacearum  n.  sp.)    U.  S.  Dept.  Agr.,  Div.  Veg.  Phys.  and 
Path.  Bui.  12:  1-28,  ph.  2.     1896. 

6.  Smith,  Erwin  F.    Bacteria  in  relation  to  plant  diseases.    8:  p.  309,  pU.  47,  figs. 

155.    1914.    Carnegie  Institute  of  Washington,  D.  C.     Publ.  27. 

7.  Stevens,  F.  L.  and  Sackett,  W.  G.    The  Granville  tobacco  wilt.     North  Caro- 

lina Agr.  Exp.  Sta.  Bui.  188:  81-96,  figs.  16.     1903. 


SPARASSIS  KADICATA,  AX  rXDKSCKIBKD  FUN(;US  ON  THK 

HOOTS  OF  CONIFERS 

j  a  m  k  h  u.  \v  k  i  r 
With  Fivk  Fic;!kks  in  tiik  Tkxt 

In  August.  1912,  the  writer  collected  s(»vt»nil  siMTiinens  of  a  sp<M'i<'>  <>f 
Sjwirjissis  growing  on  th(»  nnits  of  various  (•onif(»rs  in  the  Priest  River 
Valley,  Maho.  Lloyd,  to  whom  sjMM'iniens  wen»  sent,  pronounced  il  an 
inuh»scrilKMl  sjx'cies.  Cotton  of  the  Pathological  Laboratory*  at  Kew  wlio 
was  a<lvis4M|  hy  Lloyd  of  th<»  writ<*r's  six'ciniens  stated  that  the  plant 
w:ts  unknown  to  him.  Since  collecting  the  first  s|H»cimens.  the  writer 
luis  studied  the  |)lant  in  several  regions  of  the  Northwest  and  finds  tlutt 
of  the  many  jx^culiarities  of  the  s|KM'ies  the  most  surprising  diM*ovt»r>" 
is  its  evi<lent  parasitism  on  the  nM)ts  of  conif<Ts.  Although  this  fact  was* 
noted  in  MM 2.  it  was  not  until  the  plant  was  carefully  studied  in  ix>  n-b- 
tion  to  its  S4»V(Tal  ho>ts  that  this  ph:ise  in  its  life  historv  eouhl  Ih*  snti*- 
factorilv  determined. 

nKS<'HIPTIO\   OF  THK    KrNCiT.S 

Since  the  fungus  d<M»s  not  agn»<»  with  any  known  inemlnT  of  the  genu^. 
it  is  described  as  new. 

Sparassis  radicata  n.  sp. 

Fruiting  stnictun*  larg(^  12  to  22  cm.  ))road.  10  to  1(>  cm.  high.  dilat«-<i 
aUive.  compact.  Heshy.  tough,  whitish,  cn^amy  yeUow  with  age.  I>ninclif«|; 
hninches  numerous,  hori/^ontal  or  vertical,  anastomosing,  sometimes  fonn* 
ing  lahyrinth-like  cavities.  nion»  often  comiKictly  arnmgiMl.  ver>*  thin,  fan- 
shafMMl  with  wavy,  sometimes  din-ply  IoImmI  margins,  ocnt.'iioniilly  striat«»<i. 
aiiiphigcnou*^  or  unilateral,  de|M*nding  on  the  fMKsition  of  the  l>nin<*h. 
Malk.  H'lrrotioid.  tuU'rculate,  firm,  solid,  sometimes  hnincheil,  21)  ^{l>  mi. 
long.  .'»  s  rm.  hroail:  s|)on*«i,  ..">()<  nmgc  2.S  4.0  X  2.S-r>..')  ^,  standard  ^ir.9* 
'.iV  .'    '».l  ^.  oviiid.  hyaline. 

7*v/*»  UH-nUtij,     Pri<»st  River.  Idaho 

Ihilntni.     Living  kmiI-^  in  c'oiiiferous  tn'4'^'. 

litiHtj* .     nn*Kon.  Idaho.  \Va.*«hington.  Montana,  and  British  (\»luml*ia. 

T\tlH-  tniit*rt'il.  In  the  nffin*  of  Inv("«tigatio!w  in  Forest  PatholiH^y, 
liun-riu  fif  Plant  Industry.  Mis.s^nila,  Mont. 


1917]  Weir:  Sparassis  radicata  167 

general  morphology  and  taxonomy  of  the  genus  sparassis 

The  genus  Sparassis  was  established  by  Fries*  and  placed  in  the  Cla- 
variaceae  because  of  its  frondose  habit,  fleshy  consistency,  and  the  be- 
lief that  the  spores  were  produced  on  all  surfaces  of  the  sporophores.     It 
has  recently  been  shown  by  Cotton^  that  the  hymenium  of  Sparassis  is 
not  amphigenous  but  that  the  flattened  branches  with  the  exception  of 
those  in  the  center  of  the  sporophore,  are  unilateral.     On  the  basis  of  the 
flattened  sporophore  and  the  inferior  hymenium  Cotton  suggests  that 
Sparassis  should  be  removed  from  the   Clavariaceae  and   placed  in  the 
Thelephoracea*.     He  points  out  that  in  the  Merisma  section  of  the  genus 
Thelephora  are  species  with  upright,  partly  unilateral  sporophores  either 
terrestrial  or  growing  on  wood  which  in  many  respects  have  the  charac- 
ters of  Sparassis.     In  points  of  smoothness  of  the  hymenium  he  further 
suggests  that  Sparassis  is  alHed  to  Stereum  but  since  the  relationship 
to  Stereum  is  not  very  close  sees  no  reason  why  the  genus  Sparassis  should 
not  be  transferred  to  the  Thelephoracese  without  reference  to  any  par- 
ticular genus.     Sparassis  would  then  be  distinguished  as  a  genus  of  the 
Thelephoracese  having  fleshy,  flattened,  horizontal  or  vertical  anastomos- 
ing branches  with  unilateral  structures.     The  same  view  is  entertained 
by   Lloyd'  who  thinks  the  definition  as  laid  down  by  Fries  *' fertile  on 
both  sides ^*  should  be  corrected.     Whether  or  not  this  view  should  be 
adopted  in  view  of  the  fact  that  there  is  considerable  irregularity  in  the 
formation  of  a  unilateral  sporophore  is  doubtful.     In  young  sporophores 
of  Sparassis  crispa  (Wulf.)  Fr.  examined  by  the  writer,  also  of  Sparassis 
radicata^  the  hymenium  is  by  no  means  confined  to  the  lowermost  portion 
of  the  flattened  branches  but  is  found  more  or  less  uniformly  over  all  free 
surfaces.     This  is    particularly  true,  as    Cotton    points    out,  for  those 
branches  in  the  center  of  the  sporophore  but  with  a  more  pronounced 
unilateral  structure  toward  the  periphery.     The  hymenium  of  Sparassis 
radicata  is  formed  very  rapidly  on  the  reverse  side  of  the  peripheral  lobes 
when  changed  from  their  origninal  position.     A  few  specimens  with  un- 
usually vertical  lobes  showed  an  amphigenous  hymenium  throughout 
making  it  seem  probable  that  the  lobes  only  become  unilateral  when  they 
develop  in  a  position  allowing  the  influence  of  gravity  to  be  more  active 
on  one  side  than  another.     There  are,  however,  very  few  unilateral  fungi, 
if  any,  that,  under  proper  conditions  of  growth,  will  not  when  reversed 
develop  the  hymenium  on  the  upper  side. 

'  Fries.    Systema  mycol.,  I,  p.  462. 

•  Cotton,  A.  D.     On  the  structure  and  systematic  position  of  Sparassis.    Trans. 
British  Myc.  Soc.    1911:  336-339. 

»  Lloyd,  C.  G.     Letter  No.  61,  note  400. 


168  Phytopatholoot  [Vol 

Until  QiH'Ict*  nn<l  PatouilInnl*  iiotni  the  affiiiiticx  of  Sparassis  with  ci 
tiiiii  ifroiips  in  l)ii'  Thc-lt-pliomrcii'  Imt  iippamilly  without  ilcfinilr  knot 
i-djEi'  of  ilic  liyiiirnial  ilfvclopiiiciit  in  llic  (jt'iiiis.  Somi-wliat  later  Mai 
M-iuinilcit  Spitrassis  fniiii  tin-  < 'lavariiH-i'u'  making  it  the  ty|>p  «f  a  «pw 
family,  tlic  SiMirassiili>ii>.  AllhoUKli  Muirc's  (-lassifii-alion  wiis  udoptini 
l^itsy,'  rritioal  work  on  thi*  licvi-loiinicnl  of  the  hyincniiim.  ixTmanpn 


"Iftlk  :iltKrlin)  Ui  rhr  root* 


nf  ih..  .iMihl.-ral  -ini.-l.in-  <,f  ih.-  l,raiu-li<..  niul.-r  vari.ni^  fa.-l..r^  ..f  rh.w 

aitil  -..  lortli  i-  wry  i.iu.l.  ii.-.-l.-.i  Ui,,r.-  tli-  .■ImiiKi-  .-li.aiM  U'  a.-r.-pf 

l.l..y.l  La-  mail.,  ll..-  xiKU.-rnm  t,.  tli..   wnt..,   lli:,t   rli..  u.-iiii-  Sp^.ra- 

f:tll-  naliirally  iiili>  Iw..  M-.-ljnii-.:  tii-l   >',  r<,v,,„,  ii|„.||  „  „i,.ir  ».f  ;,  n.-l 

'  l^i.-[.i       Kl..r:.  [i.vr..|<.Ki<|ii'-  'i>-  l;i  KriM.'..      I'urj*.     Ivvs. 

'  I': ill^r.l      \j~  llviix'i yW'l.'.  .i'Kiir..]-       I'urU      IS.S7. 

■  \I:,.r.       ItirK-r.  Iir-  .->  l..l..Bi.|ii.  -  .r  l,.\..Mm,ii.|i.,>  -ur  1.-.  H«-i.l..rnv.-f.tf ,.      A 
iu-\.-  :,<t   Hull    S.M'    iinr,    tr:iii.r.  18:    -,      I'.Nrj. 

'  I...t->      V..rir.p'  iil-r  l-.tuiii«li.-  Si:,i ,.  (pmliLilnr.  t.    Jrna.     lUttV 


1917]  Weir:  Sparassis  radicata  169 

nature  especially  near  the  base  of  the  branches  and  is  very  closely  re- 
lated to  Clavaria,  and  a  second  section  consisting  of  species  with  thin 
lobes  such  as  S.  spathulata  in  the  United  States,  S.  laminosa  of  Europe, 
and  S.  radicata  which  has  thinner  lobes  than  either  of  the  former.  This 
seems  to  be  a  very  logical  arrangement.  He  further  suggests^  that  Spa- 
rassis laminosd  and  S.  spathulata  are  probably  indentical.  Their  sporo- 
phores  are  certainly  very  similar. 

THE   ROOT   STALK   OF   SPARASSIS   RADICATA 

Sparassis  radicata  (fig.  1)  differs  chiefly  from  Sparassis  crispa(WuU.)  Fr. 
{S.  ramosa  Schaff.)  which  is  reputed  common  in  the  eastern  United  States 
and  in  Europe,  S.  laminosa  Fr.  of  Europe,  and  S.  spathulata  Schw.  (Ste- 
reum  spathulatum  Schw.)  (sparassis  Herbstii  Pk.)  of  America  in  the  thin- 
ness of  its  lobes  and  by  its  very  pronounced  perennial  sclerotioid  root- 
stalk  from  which  the  sporophore  develops  annually  (fig.  2).  Since  the 
rootstalk  is  usually  attached  to  the  deeper  lateral  roots  of  its  host,  it  is 
often  of  a  surprising  length  especially  if  a  thick  deposit  of  forest  litter  has 
accumulated  around  the  base  of  the  tree.  Specimens  have  been  found 
50  cm.  in  length  but  the  average  is  from  20  to  31  cm.  No  record  exists 
of  such  a  rootstalk  for  any  other  species.  Sparassis  crispa  has  a  rooting 
base  but  it  is  not  known  to  be  perennial.  It  is  possible  that  this  phase 
of  development  is  common  to  the  other  two  species  but  has  been  over- 
looked. Sometimes  the  underground  stalk  is  divided  into  two  secondary 
ones  each  supporting  a  sporophore  (fig.  2).  The  spongy  character  of  the 
upper  portion  of  the  rootstalk  soon  merges  into  a  very  hard,  compact 
mass  and  at  the  point  of  attachment  to  the  root  has  very  much  the  ap- 
pearance of  true  cellular  structure  with  the  component  filaments  arranged 
longitudinally.  The  periphery  of  the  stalk  at  the  surface  of  the  ground 
is  composed  of  hyphae  very  much  modified  into  a  hard  encrusting  layer 
and  may  sometimes  have  a  resinous  appearance.  The  mycelium  at  the 
base  of  the  stalk  usually  cements  the  earth  into  a  hard  stone-like  body 
often  of  large  dimensions.  The  fungus  has  not  been  found  growing  in 
the  soil  unattached  to  woody  material.  It  is  doubtful  if  it  ever  does  so 
occur.     All  specimens  so  far  collected  were  found  at  the  base  of  trees. 

The  structure  of  the  rootstalk  is  not  that  of  a  true  sclerotium  although 
it  functions  as  such,  is  permanent  and  produces  new  sporophores  from 
year  to  year.  The  stubs  of  old  sporophores  are  plainly  evident  on  the 
old  root  stalk  (fig.  3)  and  as  high  as  ten  have  been  found  on  a  single  speci- 
men. It  was  expected  that  the  rootstalk  would  have  great  power  of  re- 
generation.   This  was  tested  on  July  3,  1915  by  cutting  off  a  half-grown 

«  Lloyd,  C.  G.    Letter  No.  44,  note  51,  1913. 


1917]  Weir:  Sparassis  radicata  171 

fruiting  end,  showing  not  only  the  evident  polarity''  of  the  rootstalk  but 
that  it  is  a  reserve  structure  of  considerable  reproductive  power. 

The  formation  of  sclerotioid  bodies  from  which  their  fructifications  are 
developed  is  common  to  a  number  of  Polypores.  Chief  among  these 
noted  in  western  United  States  are  Polyporus  berkeleyi,^^  P.  umbeUatuSf^^  P. 
frondoBus^  and  Lentinus  sp.,  parasitic  on  the  roots  of  conifers  and  probably 
unnamed.  The  latter  species  has  a  true  sclerotium."  Lloyd^*  lists  the  fol- 
lowing species  growing  from  sclerotia-like  structures  and  separates  them 
as  a  distinct  group  of  the  section  Ovinus  of  Polyporus:  Polyporus  tuber- 
aster  (Japan,  China,  and  Europe),  P.  Goetzii  (Africa),  P.  Sapurema  (Bra- 
zil), and  P.  Mylittce  (AustraUa).  Three  other  species  also  with  sclerotia 
but  not  included  in  this  section  are  P.  bdsilapidiodes  (AustraUa),  P.  sacer 
(Africa),  and  P.  rhinocerotis  (Malay). 

The  formation  of  sclerotioid  bodies  seems  to  be  common  to  the  Cla- 
variacese.  Some  of  the  large  species  of  Clavaria  are  observed  to  spring 
from  large  globose  masses  which  when  sectioned  exhibit  a  very  compact 
structure  and  are  known  to  last  over  for  more  than  one  year.  This  has 
been  observed  by  the  writer  for  Clavaria  aurea,  C.  amethystina  and  C. 
formosa.  The  members  of  the  interesting  genus  Typhula  always,  so  far 
as  observed,  produce  sclerotia  from  which  the  sporophore  is  produced. 
In  view  of  the  fact  that  the  sclerotia-forming  habit  seems  to  be  more  or 
less  common  to  the  Clavariacese,  together  with  the  fleshy  consistency  of 
the  sporophores,  flattened  or  cylindrical  anastomosing  branches,  large 
size  of  many  species,  amphigenous  hymenium,  constant  in  most  genera, 
irregular  in  others,  it  seems  that  this  family  is  very  well  defined.  The 
removal  of  the  genus  Sparassis  to  the  Thelephoraceae,  which  possesses  few 
or  none  of  these  characters,  would  be,  it  seems,  an  unnatural  arrangement. 

*  Weir,  James  R.  tFntersuchungen  tiber  die  Gattung  Coprinus.  Flora  n.s.  108: 
301-305.    1911. 

*•  Weir,  James  R.  Some  observations  on  Polyporus  berkeleyi.  Phjrtopath.  3: 
101-103,  pi.  9.    1913. 

Later  observed  by  Lloyd,  Letter  No.  60,  note  391,  1915;  and  Letter  No.  59,  note 
306,  1915;  and  by  Overholts,  The  Polyporace®  of  the  Middle  Western  United  States. 
Washington  University  Studies  3:  23,  pi.  2.    1915. 

"  Lloyd,  C.  G.  Letter  No.  58,  note  277,  1915;  and  Overholts  in  The  Polypora- 
ceae  of  the  Middle  Western  United  States.  Washington  University  Studies.  3:  24, 
pi.  2.     1915. 

"  Fetch,  T.  The  pseudo-sclerotia  of  Lentinus  similis  and  L.  infundibuliformis. 
Ann.  Roy.  Bot.  Gard.  Peradeniya  6:  1-18,  pi.  1.    1915. 

"  Lloyd,  C.  G.  Synopsis  of  the  Section  Ovinus  of  Polyporus.  74-76.  Oct.  1911. 
Cincinnati,  Ohio. 


172  Phytopathology  [Vol.  7 

the  disease  caused  by  sparassis  radicata 

The  observation  that  possibly  some  members  of  the  genus  Sparassis 
are  parasitic  on  the  roots  of  forest  trees  has  been  made  by  others.  In  a 
letter  to  the  writer,  dated  January  7,  1916,  Doctor  Cotton  writes:  "Spa- 
rams  crispa  has  been  found  frequently,  and  from  its  intimate  connectioo 
with  the  roots  of  Pinus  and  other  conifers  we  are  strongly  inclined  to  sus- 
pect that  it  is  parasitic/' 

Kirchmayr/^  it  appears,  was  the  first  to  entertain  the  suspicion  that 
Sparassis  had  symbiotic  or  parasitic  tendencies.  Working  with  Spara$$iM 
crispa,  he  found  that  the  stalk  of  this  species  penetrated  deep  into  the 
earth  at  the  base  of  the  tree  (Fohre).  Boring  into  the  roots  from  which 
the  fungus  appeared  to  have  sprung,  he  found  that  after  passing  througli 
a  sone  of  healthy  wood  the  auger  encountered  diseased  wood.  TUs  wood 
was  of  a  brown  color,  gave  out  a  strong  odor  of  turpentine,  and  was  very 
soft  so  that  the  auger  readily  pushed  through  it.  Two  trees  when  cut 
showed  that  the  brown  rot  extended  up  into  the  heartwood  of  the  trunk 
for  a  distance  of  two  meters.  The  decayed  wood  could  be  nibbed  into  a 
fine  powder  and  gave  out  an  odor  of  turpentine.  The  decay  resembled 
that  produceii  by  Polyporus  sidphureuSf  the  checks  extending  veitaeally 
and  |)aralleling  the  annual  rings.  The  checks  were  lined  wiUi  a  fine  my- 
celial layer  which  was  encrusted  with  granules  of  calcium  oxalate.  Larfee 
peicres  of  the  cubical  checkoil  wockI  could  Ix^  removed  from  the  hollow  in 
the  heart  wo(m1.  The  heart w(mx1  in  the  larger  roots  was  also  decajred, 
while  the  sapwocxl  was  infiltrated  with  pitch  {"verkieni'*).  The  decayed 
wcHxl  largely  dissolved  in  anmionia  prcxiucing  a  thick  brown  liquid  whidi 
on  neutralisation  held  a  brown  deposit  in  suspension. 

The  author  was  unable  to  demonstrate  the  relation  of  the  mycdium  of 
Sparannis  crinpa  with  that  in  the  disi^as^^l  w(xxl.  He  calls  attention  to 
the  fact  that  the  shrinkage  of  the  wo<n1  in  the  fonn  of  cubes  with  surfaces 
covennl  with  a  fine  white  mycelial  layer,  bn>wn  color,  odor  of  turpentine, 
and  ability  to  Ix'  niblMMl  into  a  fine  powder  an*  chanicteristic  of  the  decay 
pnnhi^Ml  by  PolyfHfrun  HchweiniUii,  In  the  writer's  experience  the  rot 
of  l^olyfHtruA  HchuTinitzii  may  not  always  Im»  acrompanied  by  the  pnxluc- 
tion  of  s|)<>n>phon's  until  a  long  timo  after  the  wcxhI  Ls  well  advances!  in 
diTay.  Sinre  din^t  ronn«M'tion  of  thr  mycelium  of  the  base  of  the  sptiro- 
phon'  with  that  of  the  d(M*ay('<l  winhI  was  not  disc*emible,  it  seems  quite 
pn»b:ibl(*  thut  i\w  invrstigator  hii^  made  an  inc(»mH*t  diagnosis. 

A  ran*ful  examination  bv  the  writer  of  six  tn»es,  the  nx>ts  of  which  lx»re 
the  fructifiration  of  SfHintssis  nuUcntn  has  not  n»vealiNl,  with  one  excvfv 

**  Kirrhiiinyr.  (Mmt  «li*ti  pHruNitiKiiiUH  v<»ii  Poly|>c>rui«  frondoflus  Kr.  umi  S|MirMi- 
•u  ranioiia  .^luifT    liodwifciii  M:  XW  .'MT.     1914. 


1917]  Weir:  Spakassis  radicata  175 

with  a  thick,  mycelial  mat  from  which  the  rootstalk  takes  its  origin.  The 
greatest  decay  occurs  at  the  point  where  the  rootstalk  is  attached  and 
is  at  first  confined  principally  to  the  sapwood.  Small  roots  originating 
from  larger  ones  to  which  the  rootstalk  is  attached  are  usually  decayed 
throughout.  The  early  decay  of  the  heartwood  in  the  larger  roots  is 
probably  prevented  by  the  large  amount  of  pitch  which  they  contain. 
Eventually  the  heartwood  is  invaded  but  is  pot  broken  down  uniformly. 
Elongated  pits  filled  with  a  white  mycelium  are  formed  in  different  parts 
of  the  wood,  often  anastomosing  in  such  a  manner  as  to  leave  long  pieces 
of  partially  decayed  or  solid  wood  which  may  be  very  readily  removed 
(fig.  5).  Sunken  areas  on  these  pieces  correspond  to  similar  pits  on 
pieces  which  have  become  wholly  disorganized.  These  elongated  pits  are 
often  bounded  by  a  white  mycelium  arranged  in  the  form  of  a  network. 
The  tissue  in  the  heartwood  is  brittle  but  can  not  be  rubbed  into  a  fine 
powder  as  described  by  Kirchmayr  for  wood  attacked  by  Sparassis  crispa. 
The  rot  of  the  heartwood  is  always  of  a  darker  color  than  that  of  the 
sapwood.  In  Douglas  fir  it  is  brown;  in  spruce,  of  a  more  yellowish  color. 
Away  from  the  seat  of  first  infection  the  mycelium  may  advance  into  the 
innermost  heartwood  causing  the  formation  of  a  pitchy  zone  next  to  the 
sapwood.  The  diseased  wood  may  be  drawn  out  of  such  roots  in  strips 
leaving  a  hollow  cylinder.  The  cambium  and  outer  bast  are  always,  how- 
ever,  permeated  by  the  mycelium  in  the  characteristic  fan-shaped  masses. 
The  action  of  the  mycelium  in  the  resin  ducts  of  the  bast  causes  a  flow 
of  pitch  which  may  cement  the  soil  to  the  root  in  stone-like  masses. 

The  fact  that  the  fungus  can  maintain  its  activity  in  the  cambium  in 
roots  deep  in  compact,  mineral  soil  is  very  unusual.  Some  of  the  root 
fimgi  which  attack  primarily  the  heartwood  may  follow  the  roots  to  a 
considerable  depth,  and  Annillaria  mellea  and  Fomes  annosus  habitually 
attack  the  cambium  to  a  considerable  distance  in  the  mineral  soil,  but  in 
the  experience  of  the  writer  no  other  species  has  developed  this  ability 
to  as  great  an  extent  as  Sparassis  radicaia.  The  decay  is  apparently 
confined  to  the  roots  proper,  never  having  been  traced  beyond  the  sur- 
face of  the  soil.  In  case  of  an  excessive  accumulation  of  forest  debris 
around  the  base  of  the  tree  the  decay  may  extend  higher  up  on  the  lateral 
roots  than  is  ordinarily  the  case  when  this  accumulation  of  materials 
does  not  occur. 

Only  two  species  of  fungi  are  definitely  known  to  parasitise  the  roots 
of  coniferous  trees  in  the  temperate  zone,  viz,  Fomes  annosus  and  ArmiU 
laria  mellea,  Rhizina  inflata}^  may  possibly  be  grouped  here  but  in  north- 
western United  States  seems  to  be  confined  principally  to  seedlings. 

^*  Weir,  James  R.  Observations  on  Rhizina  inflata.  Jour.  Agr.  Research  4: 
93-05.     1915. 


176  Phytopathology  (Vol.  7 

There  arc  a  number  of  fungi  which  attack  the  roots  of  forest  trees,  are 
not  strongly  parasitic  and  do  not  cause  a  rapid  browning  of  the  foliaiEe 
and  rapid  death.  Their  action  is  confine<l  mainly  to  the  heartwood  of 
the  roots  and  the  base  of  the  trunk.  The  most  common  of  these  is  Poly- 
porus  schweinitzii.  Other  species  which  are  either  wholly  confined  to 
the  roots  and  bases  of  trees  or  extend  into  the  roots  from  infection  through 
wounds  on  the  trunk  are  Trametes  Piniy  Echinodoniium  iindoriuni^  Poly- 
parus  sulphureuSy  Porta  trei'ni,  and  so  forth.  In  the  light  of  the  pres- 
ent status  of  the  study  it  can  not  Ix?  stated  just  how  rapidly  Spara^unn 
radic€Ua  causes  the  death  of  its  host.  It  has  not  l)een  found  on  repro<hir- 
tion  or  young  trees.  The  plant  is  not  abundant  but  sufficient  data  have 
been  assemble<l  to  show  that  it  may  l)e  placed  in  the  same  g^roup  with 
Armillaria  mellea  and  Fomen  annoaus. 

To  date  only  four  trees,  two  Douglas  firs  (Pseiuiotsuga  taxifolia),  cme 
white  pine  {Pinua  monticoUi),  and  one  spruce  {Picea  engelmanni)  have 
iKH'n  found  to  have  succuhiIkhI  to  the  action  of  the  fungus.  The  conclu- 
sion that  the  <l(»ath  of  th(^sc»  tn»es  was  causc*d  by  SjHira^Hts  rndicala  was 
arrive<l  at  l)ecau.He  of  the  absence  of  any  other  fungus  or  factor  which  has 
heretofore  l)een  accre<lite<l  as  causing  the  death  of  trees.  Several  un- 
healthy trees  with  the  fungas  on  their  roots  have  l)een  studied,  but  the 
common  n>ot  fungi  wen^  prt^^nt  making  a  cornH*t  diagnosis  impossible. 
The  fungus  has  in  ev(»r\'  ciis<»,  however,  Uvn  found  to  cause  the  death  of 
the  living  parts  in  the  nK)ts  to  which  it  wjis  attachcnl. 

HOSTS  AND  DISTRIBUTION  OF  THE  FUNGUS 

Sparanms  radicata  is  ver>'  widely  distributed  in  the  Northwest,  hav- 
ing lH»on  found  by  the  writer  in  British  Columbia,  Washington,  On^gon. 
Idaho,  and  Montana.  Sparasais  crispa  as  report^nl  from  C^alifomia  is 
ver>'  probably  bascMi  on  this  species. 

The  fungus  has  been  found  attacking  the  r(K)ts  of  the  following  conifers: 
PnewUAifuga  taxi  folia,  Picea  engelnuinni,  Pinujt  moniicola^  and  Ijorix  (Kri- 
dentalis.  Its  cK'currenc<»  on  the  nK)ts  of  broa<l-leaf  species  has  not  U^en 
note<i  by  the  writer.  Kirchmayr  cites  instances  of  the  occurrence  of 
Sparannttis  rrM/xj  on  oak  an<l  l)eech  and  other  bn)ad-leaf  species. 

SUMMARY 

The  large  s|)ecies  of  Sparassis  in  the  wwtern  Tnited  States  is  found  to 
diffiT  in  a  numlK*r  of  <ietails  from  Sptira^sis  laminosa,  »S.  crispa,  and  N. 
ttpathuUitn,  and  is  clt^scrilMHl  as  new  under  the  name  Sparansis  radicata. 

The  fungus  is  chiefly  <iistinguish(Hl  by  its  thin  lol^es  and  an  unusu- 


1917]  Weir:  Sparassis  radicata  177 

ally  large  perennial  rootstalk  which  is  of  the  nature  of  a  sclerotium  and 
from  which  new  sporophores  are  developed  from  year  to  year. 

The  most  important  feature  in  the  life  history  of  the  species  is  its  para- 
sitism on  the  roots  of  conifers.  The  myceUum  attacks  the  bast  of  the 
roots  and  later  the  wood,  producing  a  yellow  or  brown,  carbonizing  rot. 

Office  of  Investagations  in  Forest  Pathology 
Bureau  of  Plant  Industry 
Missoula,  Montana 


SOME  CHANGES  PRODUCED   IN  STRAWBERRY  FRUITO 

BY   RHIZOPUS  NIGRICANS 

N  K  I  L  E.   Stevens   a  \  d  L  o  x   A.   H  a  w  k  i  n  a* 

INTRODrCTION 

Tho  rot  rauscMl  hy  Rhizopun  nigricans  EhrenI).  in  fttrawl)ern'  fniitu 
(Fragnriii  sp.)  and  |K)tatc)  tuJ)ors  {Solanum  (uberosum)  has  l)Ocn  i«tu<iie<l 
l)V  the  writers.  In  \Hy{\\  tlu»s<»  cimk'h  as  w(»ll  as  in  others'  the  rot  caiu«eti  bv 
this  funfai-*<  in  characteriziMl  l>y  the  rapid  softening  of  the  affecte<l  tiwuf« 
aeeonipanied  hy  the  loss  of  a  Iarfi:e  amount  of  juice.  The  morpholofQcal 
chan^^s  pro<hi(*ed  in  the  straw!)err>'  by  Rhizopu.s  nigricans  have  alreaily 
Ix^en  inv(*sti^ated.  It  was  to  (»Y>tain  sonu*  information  on  the  bi<>-<*heini- 
ral  rhanf^'s  brought  al)out  in  the  strawU^rry  fruit  by  this  funinu*  that 
tlie  presc»nt  study  was  und(»rtaken.  In  this  work  the  effect  of  Hhizopu* 
nigricans  on  the  su^ar.  a<*id,  ix^ntosiin,  and  crude  fat  content  and  the 
fXTct'iitage  of  dry  matter  of  the  strawU^rry  was  studied. 

METHODS 

The  U»rries  uwd  in  this  study  wert»  all  of  the  variety  Missionary,  itniwn 
at  Vienna,  Virinnia.  and  picked  lK»twe<»n  May  2()  and  June  5,  \9U\,  The 
methcNis  for  disinfecting  an<l  .*<amplinK  us<'d  suc(*essfully  by  one  of  the 
writers  in  studit^  of  fM'ach  (3)  and  (M)tato  (5)  rots  were  found  inapplicable 
to  this  work.  The  outer  layers  of  (vlls  of  the  strawlierry  were  s<i  injuretl 
by  antis<>ptics.  such  jis  mercuric  chlorid  an<l  alcohol,  as  to  n»nder  n*suUj> 
of  doubtful  value.  es|M*ci:illy  as  it  had  already  Inhmi  <ienionstnit4Mi  that 
under  normal  moistun*  conditions  the  mynOium  of  the  funfni^  |Cn»W!i 
chicflv  in  the  outer  n'll  la  vers  (S).  The  textun*  of  the  Htrawl»errv.  «f 
coursi'.  pn»vents  |>ortions  of  the  siiine  U'rry  U'inK  u.*«<mI  for  incN'ulation 
and  r(»ntn»l.  The*  error  dut*  to  variations  in  individual  fruits  inav  lie 
.«om<*what  greater  than  where  iMirtions  of  the  same  fniits  can  lie  t^mifian'il. 

'  In  th«*  t\(MTiiiiriitf  (If.NrriUMl  in  thifi  paiMT  the  rultiirul  work  wan  lionr  by  St«^ 
vi*nH.  '\\\o  jiiiiHir  utithnr  it*  rf.«p<inHi)>lf*  fi*r  tli«*  rhciniral  work.  Th^  wrtCem  an> 
inili-htcil  t<»  Mr  A  A.  HilfV  of  iIh*  uttwv  nf  DniK-IMant.  Poiflonoun-Pltiiit.  Phymolo. 
Kiral.   ami    FiTnirntatinn  InvrntifcationH  for  nHHiHtnnnf  in  the  chemical  work. 

' 'I  ht'  litiTaturc  r«>fi'rrinK  to  thr  cfTcrt  of  lihiznpus  uigricann  <in  various  fruit« 
haa  \fvti  l>ri4'tly  rrvicwrtl  in  another  pa|)cr  tmon  to  U*  piil>liiihf*d.  Stcvena,  Neil  K. 
and  Wilrox.  H.  li  .  Uhixopuri  rot  of  fitrawU'rri<'H  in  traniiit.     l*.  8.  D.  A.  Bui.  531. 


1917]  Stevens  and  Hawkins:  Rhizopus  nigricans  179 

After  some  preliminary  experiments  the  following  method  was  found 
satisfactory  and  was  followed  throughout  the  work:  Berries  as  nearly 
uniform  in  size  as  possible  were  picked  when  nearly  ripe,  i.e.,  when  about 
half  of  the  berry  showed  a  bright  red  color.  They  were  picked  early  in 
the  morning  while  still  cool  and  covered  with  dew.  The  calyxes  were 
removed  and  the  fruit  washed  several  times  in  sterilized,  distilled  water. 
They  were  then  placed  in  wide-mouthed  flasks  which  had  been  plugged 
with  cotton  and  sterilized.  Three  or  four  berries  were  usually  placed  in 
each  flask.  The  berries  were  inoculated  with  spores  and  myceUum  from 
pure  culture,  a  strain  of  Rhizopus  nigricans  isolated  from  strawberries 
shipped  from  Florida  during  February,  1916,  being  used  for  inoculation. 

The  method  usually  followed  in  preparing  the  samples  of  fruit  for  analy- 
sis was  to  grind  the  berries  in  a  mortar  and  then  wash  the  pulp  quantita- 
tively into  the  proper  container.  The  flasks  with  the  berries  in  them 
were  weighed  immediately  before  the  fruit  was  prepared  for  anal3rsis 
and  the  washed  and  dried  flasks  were  weighed  again  after'the  berries  and 
juice  had  been  removed.  The  wet  weight  of  the  fruit  could  thus  be  cal- 
culated. All  determinations  were  related  to  wet  weight  of  the  sound 
or  rotten  fruit.  The  methods  for  the  determination  of  the  sugars,  pen- 
tosans, and  dry  matter  were  similar  to  those  followed  in  the  studies  of 
peach  brown-rot  (3)  and  the  rots  of  potato  (6). 

The  acid  content  was  determined  by  grinding  a  sample  of  fruit,  usually 
about  20  grams,  in  a  mortar,  then  allowing  it  to  stand  three  days  in  a 
flask  with  150  cc.  water  to  which  a  Uttle  toluol  had  been  added.  The  acid 
was  titrated  with  n/10  sodium  hydroxid  in  this  flask  using  litmus  solution 
as  an  indicator.  The  end-^point  in  these  titrations  was  not  as  exact  as 
might  be  desired  because  the  pigments  of  the  strawberry  which  were  pres- 
ent in  the  solution  made  it  impossible  to  detect  slight  changes  in  color. 
However,  the  determinations  are  all  comparative  and  the  differences  in 
acid  content  in  the  sound  and  rotten  berries  are  large.  The  crude  fat 
determinations  were  made  by  extracting  the  dried  and  ground  samples 
of  fruit  with  water-free  ether,  which  was  then  evaporated  and  the 
residue  dried  and  weighed.'  A  number  of  samples  of  freshly  picked  sound 
berries  were  analyzed  to  obtain  some  idea  of  the  variation  in  the  con- 
tent of  the  compounds  determined  between  the  individual  samples.  The 
results  of  these  analyses  are  shown  in  table  1. 

From  table  1  it  may  be  seen  that  there  is  some  variation  in  the  content 
of  the  compounds  determined,  especially  the  acids  and  sugars.     The 

'  Wiley,  H.  W.,  ed.  Official  and  provisional  methods  of  analysis.  Association 
of  Official  Agricultural  Chemists.  As  compiled  by  the  conmiittee  on  revision  of 
methods.  U.  S.  Dept.  Agr.,  Bur.  Chem.  Bui.  107  (rev.),  272  p.,  13  fig.  1908.  Re- 
printed, 1912. 


180 


Phytopathology 


(Vol.7 


TABLE  1 


Showing  the  content  of  sugars,  pentosans,  acids,  crude  fats,  and  dry  maUer  infreski^ 

picked  strawberries.    Three  separate  samples  used  in  the 

determination  of  each  substance 


PBBCBIfTAOB 
WCT  WBIOBT 

AOD  AS  CC. 

KOBMAL  ACID 

rBB  100  OBAMB 

WBT  WBIQHT 

RBDUCINO 

SUOABII  AB  PBB- 

CBNTAOB   WBT 

wxioirr 

BrCROBB   AS 
PBBCBNTAOB 
WCT  WCIORT 

CBUDC  rATB   AS 
rCBCCNTAaB 
WBT  WCIOBT 

OCT  MATTSC 

AC  rscaurTACS 

WCT  WCMBT 

0.57 
0.59 
0  56 

2    59 

2.10 
2.15 

2.89 
3  67 
4.03 

1     37 

1  69 
1  65 

0  27 
0.29 
0.34 

7  97 
8.17 

8  15 

variation  in  pentosan  content  is  slight.  There  is  a  considerable  amount 
of  sugar  and  the  acid  content  is  rather  high.  The  l)errie8  of  course  weir 
not  ripe  when  picked  and  analyzed  but  wen*  at  al>out  the  stage  of  ma- 
turity at  which  they  are  har\'e8ted  in  some  sections  of  the  South  where 
this  variety  is  ^own  commercially.  A  comparison  of  the  results  of  the«e 
determinations  and  the  data  obtained  from  the  analysis  of  the  sound 
strawlH»rries  which  were  analvzed  three,  8(»ven,  or  fourteen  da>'8  after 
har\'esting  gives  some  data  on  the  (*hanges  which  take  place  in  picked 
strawl)erries  during  ripening. 

In  table  2  is  shown  the  pentosan,  acid,  sugar,  and  crude  fat  content 
and  the  percentage  of  total  dr>'  matter  in  the  sound  and  rotted  samplen 
of  fruit  at  different  times  after  harvesting.  The  analyses  are  also  of  some 
interest  in  showing  the  amount  of  the  various  sul>stances  in  the  straw- 
lK»rr>'  fruit.  (Considerable  work  hjis,  of  cours<».  already  been  done  on 
this  subject  by  various  investigators.  A  review  of  much  of  this  work 
is  given  by  Wehmer  (9,  p.  284-285).  In  table  2  the  rc9ult«  given  are 
averages  of  at  least  three  determinations  of  the  various  compounds  on 
as  many  separate  samples. 

TABLE  2 

Comparatire  pentosan,  arid,  sugar,  and  crutie  fat  content  and  the  amount  of  totai  dry 

matter  in  sound  and  rotten  strauberries 


rCWTOBAMB 

4B  rBKCRNT- 

AOB   WCT 

WBKiirr 
0  51    0  51 

1 

0  :js  0  .TJ 

ATiD  ro^rtBjrr 

AH   CC      KOBMAL 
ACID,  rcB   100 

oMfi.  09  rBrrr 

li  '  li 

1       i    :2 

1  9H      1   H9 
0  7r>     1  4'.» 
0  73      1   .V> 

BBOrclMQ 

•lUABB 

AB  rBRCBNTAUB 

WBT  WB|(«HT 

BrCBOBB 

AS  rBaCBMTAQB 

WBT   WBIUHT 

CBCDC  FAT 

ooirrcirr 
AC  rcccnrrAOC 

WCT  WCtUMT 

OCT  MATTBC  IC 
•nLAWCKCCT 

AC  rccrciTTACS 

W«T  WCMVf 

w 

1  95      1  :Ci 
0  44  ■  0  13 

li      li 
1-    '  1- 

0  36 
0  34 

P 

P 

P 

3 

1 
14 

1  w»    0  fki 

0  Jf)  '       0 

0  40 
0  31 

7  19 
««3 

«19 
5M 

1917]  Stevens  and  Hawkins:  Rhizopus  nigricans  181 

From  the  results  shown  in  table  2  it  seems  that  the  pentosan  content 
is  no  lower  in  the  rotten  fruit  three  days  after  inoculation  than  in  the 
corresponding  sound  samples.  There  is,  however,  a  decrease  in  the 
pentosans  as  calculated  on  a  wet-weight  basis  after  the  fimgus  has  acted 
fourteen  days.  It  seems  probable  then  that  the  fungus  utiUzed  a  por- 
tion of  the  pentosans.  It  is  interesting  to  note  that  there  is  a  somewhat 
similar  decrease  in  the  percentage  of  dry  weight  in  the  inoculated  berries 
in  two  weeks  so  that  if  the  pentosans  were  calculated  on  the  basis  of  dry 
weight  at  the  time  of  analysis  the  percentage  of  the  furfurol  yielding  sub- 
stances in  the  sound  and  rotten  fruit  would  be  approximately  the  same. 

The  effect  of  the  fungus  upon  the  acids  seems  to  be  to  reduce  the  acids 
slightly,  as  the  acid  content  after  the  first  three  days  is  somewhat  lower 
in  the  rotted  samples  than  in  the  corresponding  sound  ones.  The  acid 
content  of  the  soimd  berries  decreased  rapidly  until  at  the  end  of  seven 
days  it  was  only  about  half  that  of  the  rotted  berries,  and  a  similar  ratio 
k  evident  seven  days  later.  From  a  comparison  of  the  acid  content  of 
the  soimd  berries  in  table  2  with  that  of  the  freshly  picked  berries  shown 
in  table  1  it  is  evident  that  there  is  a  gradual  decrease  in  the  acidity  the 
longer  the  berries  are  allowed  to  stand  and  that  this  decrease  is  much 
more  rapid  in  the  first  week.  That  this  decrease  was  not  due  to  a  neutrali- 
zation of  the  acid  by  ammonia  either  in  the  sound  or  rotten  fruit  was 
shown  by  the  negative  results  obtained  from  several  series  of  ammonia 
determinations  by  Folin's  method.  The  acid  is  apparently  used  up  by 
the  berry  in  its  metaboUsm,  probably  in  respiration.  That  the  decrease 
in  acidity  in  the  sound  fruit  was  greater  than  that  in  the  rotted  berries 
seems  to  indicate  that  the  mechanism  for  the  utilization  of  this  acid 
is  destroyed  or  its  action  vihibited  by  the  fungus.  The  fungus  apparently 
uses  little  of  the  acid. 

The  sugar  content  of  the  rotted  berries  is  always  lower  than  that  of 
the  sound  fruit  of  the  same  series  of  samples.  A  comparison  of  the  per- 
centage of  sugars  in  the  sound  fruit,  as  given  in  tables  1  and  2,  shows  that 
the  sugar  content  rapidly  decreases  after  the  strawberry  is  harvested. 
The  sugars  as  well  as  the  acids  are  apparently  used  by  the  strawberries 
in  respiration  or  in  other  metaboUc  processes.  The  much  more  rapid 
decrease  in  sugar  content  of  the  inoculated  fruit  is  evidence  that  the  fun- 
gus uses  the  sugars. 

The  percentage  of  ether  soluble  material  in  the  soimd  and  rotted  ber- 
ries, considered  in  the  tables  as  crude  fats,  does  not  undergo  any  decided 
decrease  when  the  berry  is  rotted. 

The  percentage  of  dry  matter  in  the  rotted  berries  is  less  than  in  the 
sound  fruit. 

As  has  been  mentioned  above,  this  strawberry  rot  is  characterized  by 


182 


Phytopathology 


(Vol.  7 


a  rapid  softening  of  the  tissue,  the  loss  of  water,  and  apparently  a  itenend 
collapse  of  the  l^rry.  It  was  considered  of  interest  in  this  connectioD 
to  determine  the  amount  of  sugar  and  acid  present  in  the  juice  which 
escapes  from  the  inoculated  l)erries  as  compared  to  that  in  the  juice  of 
healthy  berries  picked  at  the  same  time  and  maintained  under  the  same 
conditions  of  moisture  and  temperature.  For  this  experiment  the  two 
samples  of  I)errie8  were  picked,  washed  in  -  sterilized  water,  and  placed 
in  liter  flasks.  The  l)erries  in  the  one  flask  were  inoculated  with  Rhiio- 
pus  in  the  usual  way.  while  those*  in  the  other  flask  were  maintained  is 
controls.  The  flasks  weiv  filled  to  the  wime  height  and  were  allowed  to 
stand  in  the  lal)oratory  for  three  days.  The  juice  was  then  poured  off 
the  inoculated  fniit  and  the  lx»rrics  of  the  control  sample  were  froipn 
with  carl)on  dioxid,  and  the  juicv  expn^sstnl  with  a  fniit  press.  The  migar 
and  the  acid  content  of  the  samples  of  juice  from  Iwth  lots  of  berries  were 
determined  according  to  the  usual  method.  The  results  are  shown  in 
table  3. 

TABLE  3 
Sugar  and  acid  contrut  of  juice  from  nound  and  rotted  utrawberrieM 


nf-iiAK  (rzmcr.sr\u%) 

ATIDITT  INTBMIi 

i  or  iioBMAi.  Mem 

Juice  frtMn  kmiimI  (niit                         Juice  fruni  ruCUtd  fruit 

Juice  frtMn 
•ound  fruit 

Jui»trom 
rotlifti  irmt 

Rfvlucinc  ■UfAT 

SucnM*         '  K«Hluctnc  sucAr 

Sucrraw 

2.66 

2  9S 

0.62 

0.14 

0  191 

0  208 

DifTunion  tension  in  Atmonphon^a. 


jncB  rmoM 
•ocMD  mcrr 


0  604 
8.37 


iricB 


1  037 
12.50 


From  tabh*  3  it  is  appan^nt  that  the  acidity  of  the  juice  from  the  di»- 
c:i.s4m|  lK*rri(*s  is  .nlightly  higher  than  that  of  the  juice  from  the  sound  oneti, 
while  th<*  ."iugar  content  is  considerably  lower.  In  table  2  it  is  shown 
that  the  sugar  content  of  the  dis<*a.^Mi  fniit  thnv  days  after  inoculation 
\va>  <l<'cn'iL»*<M|  consi(h»ral>ly  Ih*Iow  that  of  the  control  samples.  This 
may.  of  coursi',  account  for  jmrt  of  the  diffen»nce.  Howex'er,  the  suirar 
rimtent  of  till'  ino<ulated  InTries  after  thnn*  clays  is  a  little  over  half  that 
of  the  >4iun<i  fruit,  while  the  sugar  content  of  the  juice  that  leaks  out  of 
tlie  rotted  fruit  i>  alMMit  one-eighth  that  of  the  jui<*e  expressed  from  s<iund 
Urrie**.  Th<*  utilixation  of  th«'  ^ugar  by  the  fungus,  then,  can  lianlly 
.'irrniiiit  eiitiri'Iy  for  tli«'  lower  sugar  <*onteiit  of  the  juic<*  from  the  inucnilated 
li«*rri«*>  and  much  of  the  sugar  must  still  n'lnain  in  the  infected  fruit. 


1917]  Stevens  and  Hawkins:  Rhizopus  nigricans  183 

Other  materials  than  sugars  and  acids  are,  of  course,  present  in  the 
strawberry  juice.  In  order  to  obtain  some  idea  of  the  amount  of  substance 
in  this  watery  extract,  freezing  point  determinations  were  made  on  the 
two  samples  of  juice.  These  determinations  were  made  with  a  Beckmann 
freezing  point  apparatus  in  the  usual  way.  The  depression  of  the  freez- 
ing point  (A)  of  these  juices  below  that  of  distilled  water  and  the  calculated 
diffusion  tension  (7,  p.  30-31)  or  osmotic  pressure  of  which  these  juices 
are  capable  are  shown  below: 

The  freezing  point  of  the  juice  from  the  rotted  berries  is  considerably 
lower  than  that  of  the  juice  from  the  sound  fruit.  As  calculated  by  this 
method  the  solution  from  the  rotted  berries  has,  obviously,  a  higher  dif- 
fusion tension  than  that  from  the  sound  fruit.  The  juice  from  the  rotted 
berries  then  is  a  more  concentrated  solution  of  some  substance  or  sub- 
stances than  is  the  juice  from  the  sound  fruit.  From  these  experiments 
with  the  juice  from  the  sound  and  rotted  fruit  it  is  evident  that  the 
juice  which  escapes  from  the  rotted  berries  contains  at  least  a  part  of  the 
soluble  matter  that  is  present  in  the  cell  sap  of  the  berry  before  it  is  attacked 
by  the  fungus. 

DISCUSSION 

The  effect  of  the  fungus  upon  the  various  constituents  of  the  straw- 
berry as  shown  in  the  foregoing  pages  is  much  the  same  as  has  been  shown 
for  other  fungi  and  other  host  plants  in  similar  studies.  Most  fungi 
apparently  utilize  the  sugars  in  their  hosts  when  growing  parasitically. 
This  has  been  shown  by  one  of  the  writers  in  the  case  of  the  brown-rot 
disease  of  the  peach  (3)  and  some  of  the  Fusarium  rots  of  potatoes  (6). 

That  the  fungi  sometimes  lower  the  pentosan  content  of  their  host 
when  living  parasitically  has  also  been  shown  (4,  6).  Rhizopus  nigricans 
apparently  does  not  utilize  the  acids  of  the  strawberry  to  any  extent. 
Some  fungi  are  apparently  able  to  use  the  acids  in  their  host  plant  while 
others  are  not,  probably  depending  on  the  ability  of  the  fungus  to  assimi- 
late the  specific  organic  acids  that  are  present  in  the  host.  Behrens 
(1,  p.  700-706)  has  shown  that  the  acids  in  apples  can  be  used  by  fungi. 
Sclerotinia,  however,  apparently  had  little  effect  on  the  acids  in  the 
peach  fruit  (3). 

In  considering  these  results  it  should  be  remembered  that  at  the  time 
of  the  first  analysis,  i.e.,  three  days  from  the  time  of  inoculation,  leak 
had  progressed  to  an  advanced  stage.  That  is,  the  berries  were  flattened 
and  a  large  amount  of  juice  had  escaped.  At  this  time,  as  shown  by  table 
2,  only  relatively  slight  changes  have  taken  place  in  the  amounts  of  the 
various  constituents  for  which  analysis  was  made.  There  is  apparently 
no  difference  in  the  pentosan  content  between  the  rotted  berries  and 


184  Phytopathology  (Vol.  7 

sound  berries  of  the  same  af^,  and  the  difference  in  the  amount  of  acid 
present  is  very  slight.  Some  reduction  in  the  amount  of  sugar,  liolh 
sucrose  and  reducing  sugar,  has  of  course  occurred  but  as  the  sugar  was 
probably  chiefly  contained  in  the  cell  sap  this  change  offers  no  due  a« 
to  the  cause  of  leaking. 

The  bio-chemical  studies  have,  then,  served  to  confirm  the  conrlusioo 
derived  fruni  the  hu^tological  study  that  the  changes,  detectable  by  the 
methods  followed,  which  have  taken  place  in  the  cells  of  the  strawljerry 
at  the  time  leak  occurs  are  relatively  slight.  The  histological  study 
showed  that  the  cell  walls  of  the  8trawl)erry  are  seldom  pierced  by  thr 
fungous  hyphae  and  that  the  protoplasm  of  the  cells  is  only  slightly  alterpd 
in  appearanc(\  the  nuclei  in  particular  retaining  their  normal  appearaner 
until  the  c<»lls  are  crushed. 

In  a<*counting  for  the  losj<  of  juice  which  occurs  in  strawberries  attacked 
by  Hhizopuji  nigricann  the  only  tenable  hypothesis  seems  to  Yye  that  thr 
fungus  so  affects  the  protoplasm  of  the  cells,  perhaps  by  secreting  soaie 
toxin,  that  it  is  no  longer  capable  of  functioning  as  a  semi-permeable 
membrane.  In  this  connection  it  is  interesting  to  note  that  (lortener  and 
Blak<»sl<H»  (2)  have  n»cently  demonstrated  the  presence  of  a  substance  in 
Khizopus  which  is  extn»mc»ly  toxic  to  rabbits.  Whether  the  proti>pla«iD 
of  thi»  strawl)erry  is  kille<i  at  once  by  the  fungus  or  whether  it  is  anr** 
thetized  an<l  rendenni  permeable  to  the  material  dissolve<l  in  the  cell 
sap  is  an  op<»n  (|uestion.  Further  investigations  on  this  subject  mrp 
planned. 

BiRKAr  OF  Pla.nt  Indistry 
Washimjton,  I).  (\ 

LITKHATrUK  (UTKD 

1.  Hkhkk.ns.  Joiiawkh.     IVitrnf^o  lur  Konntnis  dor  (HMtfaulniii.     CVntM.   liakt  . 

AUi.  2.  i:  7(«)-7(m.     IKIW. 
'J.  (lOKTENKK.  K.  A.,  and  Hlakkslkk.  .\.  F.    (>lMu*rviitiontt  on  the  toxin  of  Khiiop^M 

nifcriranH.     .\ni«>r.  Jour.  PhvKiol.  94:  XA-lVu.     1014. 

3.  liAmxiNs.  L.  A.     SoriK*  rfTfrtH  of  th<*  l»rown-rot  fiinguii  on  the  r(»mpo«ition  of 

thr  jx'arh.     Afiirr.  Jour.  liot.  2:  71  SI.     HH.'i. 

4.  —      Th<*  utihiati<in  of  r«'rtain  p<*iitoH4'H  and  roni|M>undN  of  pcntoum  hy  (tlo 

H'lla  rinfculata.     Ainrr.  Jour.  Ii«»t.  2:  :C'>  .'iSS.     191.V 

5.  Thr  dim*a»M*  of  |Mitat4N'H  known  an  "Irak."     Jour.  \gr.  Uciioarrh  S:  fU7 

t\.      --        I'ifTiM't   of  rrrtain  K|M'<*ic^  of  KuMariuni  on  tht*  rompodition  of  thr  p«»tAto 

ixi\n'T.     J«Mir.   Aicr.   Kf-MNinh  6:  lH.VP.m.     lUHi. 
7.  LiviN(«M<i\.  H    K      Th«'  nMf  of  ditTuHJon  and  o!«nioli(*  pn*fuiurr  in  pUnta.     149  p 

('hir.'iKo.     hit>ho|craphy.  p.  '2.     llNKi. 
H    Sti.\kn^.   Nkii.  K.     I'athotoKical  hiHto|o|cy  of  HtrawlM'rriotf  affected  by 

of  liotr>ti«  and  Khiz<ipui4.     Jour.  Agr.  HriM^arrh  6:  361-306.     1916. 
\t.  \\i:iiyKit.  <*\Ki.      I)i«*  Pflanz(*ni«tofTv     ....     \KVt   p.     Jrna.     1911. 


WITCHES-BROOMS  ON  HICKORY  TREES 

F.  C.  Stbwabt 
With  One  Figure  in  the  Text 

In  Ontario  county,  New  York,  trees  of  the  shell-bark  hickory,  Carya 
ovaia,  occasionally  bear  witches-brooms  apparently  caused  by  the  fungus 
Microatrama  juglandis  (Bereng.)  Sacc.  During  winter,  while  the  trees 
are  bare,  the  "brooms"  are  readily  detected  at  a  considerable  distance. 
They  are  typical  witches-brooms  consisting  of  compact  clusters  of  short, 
upright  branches.  They  are  of  all  sizes  up  to  about  two-thirds  of  a  meter 
in  diameter  in  the  bare  state  and,  of  course,  considerably  larger  when 
in  foliage.  As  many  as  thirty  "brooms"  of  various  sizes  have  been  ob- 
served on  a  single  large  tree. 

The  leaves  on  the  "brooms"  are  yellowish  green  above,  and  white  and 
mealy  with  Microstroma  spores  on  the  under  surface.  Usually,  they  are 
smaller  than  normal  and  much  curled.  In  mid-summer  they  blacken 
on  the  margins,  then  wither  and  fall  prematurely.  The  fallen  leaves  are 
not  replaced  by  new  ones  as  happens  with  the  cherry  witches-brooms 
caused  by  Exaascus  cerasi.  The  branch  bearing  the  "broom"  is,  usually, 
considerably  enlarged  at  the  point  of  attachment  of  the  "broom"  and 
often  dead  beyond  the  point  of  attachment. 

The  constant  occurrence  of  Microstroma  juglandis  on  the  leaves  leads 
to  the  belief  that  this  fungus  is  the  cause  of  the  "brooms."  Almost  every 
leaf  on  every  "broom"  shows  the  fungus  over  its  entire  under  surface 
while  the  leaves  on  all  other  parts  of  the  tree  may  be  wholly  free  from 
Microstroma.  The  presence  of  the  fungus  becomes  evident  as  soon  as 
the  leaves  unfold  in  the  spring.  This  condition  of  affairs  is  not  rare.  It 
has  been  observed  during  seven  consecutive  seasons  on  a  large  number 
of  "brooms"  on  nine  separate  trees  in  three  localities — Geneva,  Canandai- 
gua  and  Victor. 

On  the  other  hand,  Microstroma  jiiglandis  has  long  been  known  as  a 
parasite  on  the  leaves  of  walnut  and  hickory  and  is  widely  distributed 
in  Europe  and  America;  yet  its  association  with  witches-brooms  has  not 
been  previously  recorded.  In  fact,  the  writer  has  been  imable  to  find  any 
published  account  of  witches-brooms  on  hickory  trees.  The  writer,  him- 
self, has  occasionally  observed  M,  juglandis  on  the  leaves  of  hickory  trees 
which  bore  no  witches-brooms.     At  Geneva,  in  1916,  this  was  of  com- 


[917]  Stewart:  Witches-Brooms  in  Carya  187 

)f  the  leaflets  were  attacked  by  Microstroma.  On  an  adjacent  branch 
-here  was  a  larger  "broom"  every  leaf  of  which  was  covered  with  Micro- 
itroma,  but  none  of  the  other  leaves  on  the  tree  were  affected.  A  later 
examination,  made  on  July  2,  revealed  no  change  in  the  "broom"  except 
hat  the  margins  of  the  affected  leaflets  had  begun  to  blacken.  Further 
>bservations  were  impossible  owing  to  the  accidental  destruction  of  the 
^oung  "broom." 
New  York  Agricultural  Experiment  Station 
Geneva,  New  York 


A  NEW  LEAF-SPOT  DISEASE  OF  CHERRIES 

Bert  A.   Rudolph 
With  Three  Figures  in  the  Text 

In  August ,  1913,  a  conspicuous  loaf-spot  disease  of  sweet  cherries  was 
ol)ser\'ed  by  the  writer  near  San  Jose,  California,  and  specimens  have 
lM*en  received  from  the  principal  cherr>'  growing  sections  between  Red- 
lands,  California,  and  Cor\'allis,  Oregon.  No  mention  of  it  has  been 
found  in  any  of  the  literature  examined.  Descriptions  were  sent  to  F.  C. 
Stewart,  Ceneva,  New  York;  Howard  S.  Heed,  BIacksbui|s,  Virfinia; 
M.  B.  Waite,  Washington,  I).  C.,  and  Donald  Reddick,  Ithaca»  New 
York,  and  all  expn\sse<i  doubt  as  to  its  occurrence  in  their  localities.  It 
is  lH»lieve<l  to  Ik;  jx^culiar  to  the  Pacific  coast. 

IVa<i,  definite,  circular  spots  from  one  to  al)OUt  14  mm.  in  diameter 
ap|K*ar  on  the  leaves.  The  dea<l  areas  are  a  pronounced  reddish  brown 
or  chestnut  to  mahogany  color,  and  are  .sharply  differentiated  from  the 
living  ti.Hsue,  exten<ling  from  epidennis  to  epidermis  and  commonly  marked 
with  a  delicate,  (*(>n(*entric  zonation  consisting  of  narrow  lines  and  liarker 
bands.    St»vcTal  spots  may  coalesce*  to  fonn  one  large  one. 

i  )n  the  upper  surfa<*e  of  the  leaf  may  nearly  alwa^'s  l)e  found  a  minute. 
whitish  gray  pustule  lo(*ated  in  the  <*enter  of  the  s|M>t,  and  about  which 
the  zones  an*  concvntric.  The  pastules  an'  upliftcnl  bits  of  epidermal  leaf 
ti.NSue,  and  a  minute  inM*ct  of  the  family  Chalcididae  has  regularly  lieen 
found  in  tliein. 

Within  the  s|M>t  then*  may  U»  a  definite,  centnd.  circular  portion  which 
i>  lighter  than  the  n*main<ler.  This  inner  an*a  sometimes  reaches  0  mm. 
in  diameter  and  is  ochra<vus  to  f(*rnigineus  (Saccanlo's  Chromotaxia^ 
or  it  ni:iy  U*  entin*ly  absent.  The  darker  portion  is  ciLstaneiis  to  badius. 
Th«*  pw«tul«».  if  pn'H»iit.  is  Ineated  in  the  eentiT  of  the  inner,  lighter  area. 
if  •*ueh  an  nrvii  nreurs.  The  nnd(*r  sid(*  of  the  s|M)t  pn*sents  a  slightly 
dilTtTtht  <'n|nr  frmn  the  up|MT.  The  inner  lighter  an*a  is  isaliellinus,  antl 
thi'  retii.'iiiiiiiK  |M»rtinii  Irttfricius.  iK'ing  lighter  than  the  com*s|H»ntiing 
ana  nn   the  up|MT  surfaer. 

Tlif  «l«Md  ti^^^ue  n'niaiii*<i  intact    within   tlu*  leaf. 

Soiiiftiiiir^  ihf  s|M>t-«  *ipn'ad  niit  in  an  irretrular,  Mimewhat  indefinite. 
nn»*:iif-liki'  fa*«hiori   i  tig.    1;. 


1917]  Rudolph:  Leaf-Spot  Disease  of  Cherry  191 

The  details  of  subsequent  inoculations  are  recorded  in  the  writer's 
thesis,  deposited  in  the  library  of  the  University  of  California.  In  all, 
over  two  hundred  inoculations  were  made  on  the  following  varieties  of 
cherries;  Royal  Ann,  Richmond,  Morello,  Black  Tartarian,  seedling  sweet 
cherry  and  California  Wild  Cherry  (Prumis  ilicifolia  Walp.).  During 
the  winters  of  1913  and  1914  experiments  were  confined  to  the  leaves  of 
seedlings.  In  the  spring  of  1914,  however,  large  numbers  of  inoculations 
were  made  upon  the  various  named  varieties.  The  method  of  inocula- 
tion was  the  same  as  that  described  earlier.  Checks  were  made  on  one 
side  of  the  mid-rib  and  inoculations  with  a  flamed  needle  on  the  opposite. 
Not  more  than  ten  of  all  the  inoculations  made  in  this  manner  were  nega- 
tive. In  most  of  the  inoculations  no  bell-glasses  were  used,  and  the  spots 
developed  quickly,  although  less  rapidly  than  where  covered.  About 
twenty  other  inoculations  were  made  in  lots  of  two  to  five  by  laying  bits 
of  the  fungus  in  agar  on  the  leaves  without  puncturing  or  injuring  them  in 
any  manner.  All  these  were  negative.  The  greater  part  of  this  work 
was  done  in  a  greenhouse  without  heat. 

The  fungus  is  particularly  active  when  inoculated  in  the  leaves  of  Cali- 
fornia Wild  Cherry.  About  three  dozen  inoculations  were  made  on  this 
plant,  and  not  more  than  five  proved  unsuccessful.  Frequently  arti- 
ficially inoculated  leaves  were  so  badly  affected  as  to  be  shed  from  the 
tree.  This  was  especiaUy  conunon  when  the  trees  were  kept  under  bell- 
glasses.  The  spots  produced  differ  greatly  in  color  from  those  on  the 
leaves  of  sweet  cherries.  There  is  usually  a  circular,  inner  area  in  each 
spot  which  is  avellaneus  on  the  upper  side  and  isabelUnus  on  the  lower. 
The  remaining  or  outer  portion  of  the  spot  is  isabelUnus,  and  the  lower 
side  latericius.  At  times  the  spots  may  be  a  deep  brown  color,  especially 
when  formed  more  slowly. 

Microtome  sections  made  of  the  freshly  produced  spots  stained  with 
Congo  red  and  methylene  blue  show  best  the  action  of  the  fungus.  The 
parasite  is  intercellular.  The  chloroplasts  of  the  cells  lying  just  beyond 
the  tips  of  the  advancing  mycelium  are  first  affected  and  cannot  be  dis- 
tinguished. The  cells  collapse  and  disintegrate  rapidly  as  the  fungous 
threads  come  in  contact  with  them. 

All  inoculations  in  the  bark  and  wood  of  normal  cherry  twigs  were  nega- 
tive. Over  two  dozen  inoculations  were  made  on  stems  up  to  2.5  cm.  in 
diameter.  The  bark  was  first  sponged  with  alcohol.  Slant  cuts  were 
made  with  a  flamed  scalpel  and  the  infectious  material  placed  beneath 
the  flap,  or  inoculations  were  made  by  puncturing  the  bark  through  the 
spore-bearing  material.  Both  types  of  inoculations  were  either  left  ex- 
posed or  wrapped  with  thoroughly  boiled  linen  strips  or  bound  in  absor- 
bent cotton.  Checks  were  also  made  in  the  same  way.  The  wounds 
healed  normally,  the  plants  apparently  being  unaffected  by  the  fungus. 


102 


Phytopathology 


(Vol.  7 


When  inoculated  in  the  leaves  of  other  plants  the  results  are  often  as 
pronounced  as  in  the  cherr}'  leaves.  The  leaves  were  first  sponfced  with 
alcohol  and  the  inoculations  and  checks  were  made  in  the  usual  man- 
ner.   The  results  obtained  are  shown  in  table  1. 


TABLE  1 


ResuiU  of  inoculations  of  leaves  of  various  hosts  with  a  species  of  Allernaria  fi 

cherry  leaves 


HOST 

mtmvvn 

OBMtBTAnolM 

Apple  (Pynis  Malus  L.) 

Winesap 

Newtown  Pippin 

Box  Elder  (Acer  negundo  L.) 

Hungarian  prune  (Prunui4  domestica  L.) 

Wickson  plum  (Prunus  triflora  Roxb.), 
(P.  Simonii  Carr.)  hybrid 

Orange  (Citrus  nobilis  Ix>ur.) 

King  Mandarin 

Loquat  (Kriobotr>'a  japonica  Lindl.)... 

Potato  fSolanum  tulierosum  L.) 

Avocado  (Persea  gratissima  (iaertn.).. 

Watermelon   (Citrullus    vulgaris 
Schrad.) 

Pearh  (Prunus  pc'rsica  S.  A  Z.)  Oaw- 
fcird  p<»ai'h 

20 
25 
50 
18 

•6 

20 
21 
30 

10 
40 

All  positive 
All  positive 
All  positive 
All  positive 

All  positive 

Doubtful 
Negative 
Negative 
All  positive 

All  positive 

Positive 

Jjirge  reddish  spota 
Large  reddish  «poU 
Large  brown  spoU 
Small    brown  spoU. 
Developed  slowly 

Small   brown   spoU. 
Developed    slowly 

Spots  liarely   Urfsr 

than  on  therheeki 
Spots  no  larger  than 

on  the  checks 
Spots  no  larger  than 

on  the  checks 
Large  reddish  brown 

spotii 

Black  spots.     Devel* 
oped  slowly 

Irregular    gray* 
brown  spots 

In  ^*m*nil  it  wiis  found  that  the  funj^is  prcxluctMl  its  optimum  ftrowth 
in  the  If'uf  tissue*  when  tlu*  atniosphon*  W!is  moist  and  warm  and  sunliKbt 
at  a  niiiiiriiuin.  The  men*  shading  of  an  infected  leaf  with  a  piece  of 
pajMT  was  found  to  fH'nnit  the  prcMJue'tion  of  largtT  spots  in  a  nhorter  time 
than  whrn*  the  leavers  were  exi)os<»d  to  direct  Kunlif2:ht.  The  fungus  is 
a  typi(*al  wound  panu^ite.  all  incx'ulations  on  uninjured  leaves  ha\*iiig 
failiMl.  Whrn  a  young  leaf  w:is  incK'ulated  lH»fon»  Innng  fully  developed 
a  shot-bolf  I'fTtTt  M)mrtim(v  n'sulted  on  its  exiuinsion. 

The  fungus  gn»w  vigorously  on  the  conunon  culture  media,  and  its 
more  imfMirtant  characteristirs  an*  as  follows: 


1917]  Rudolph:  Leaf^pot  Disease  op  Cherry  193 

On  non-nutrient  agar.  Growth  rapid,  mostly  confined  to  the  surface 
of  the  medium  which  is  not  discolored.  A  small  amount  of  long,  aerial, 
dry,  silky,  gray-white  myceUum  is  produced.  Spores  thinly  scattered 
over  the  surface  of  the  medium. 

On  nutrient  agar  (containing  meat  extract,  peptone  and  salt.)  Growth 
vigorous,  a  copious  aerial,  downy  mycelium  is  developed  consisting  of 
long,  branched,  silky,  gray  hyphae.  Spores  commonly  produced  in 
greatest  numbers  in  concentric  zones  which  are  dark  green  at  first  becom- 
ing sooty  black  with  age.  The  spores  are  oUvaceus  under  the  microscope. 
The  agar  is  cleared  of  any  cloudiness  by  the  fungus  as  it  develops. 

On  steamed  rice.  Growth  vigorous.  A  snow-white,  aerial,  downy 
myceUum  first  develops  which  darkens  to  a  dirty,  greenish  gray  with  age. 
A  flesh-colored  peUicle  is  produced  upon  the  surface  of  the  medium  darken- 
ing with  ^e  to  black.  The  rice  grains  gradually  become  colored  a  Ught 
yellow.  Spores  are  produced  close  to  the  surface  of  the  pellicle  and  be- 
neath the  longer  aerial  hyphae.  They  are  pale  oUvaceus  imder  the 
microscope. 

On  bread  and  prune  juice  (Duggar's  Fungous  Diseases  of  Plants,  p.  24). 
Growth  vigorous.  A  copious,  downy,  aerial  mycelium  is  produced  which 
is  dull  white  at  first  becoming  a  dirty  greenish  gray  with  age.  Patches 
of  older  parts  of  the  aerial  mycelium  are  often  yellowish.  A  cream  colored 
peUicle  is  formed  on  the  surface  of  the  medium  becoming  black  with  age. 
Spores  develop  close  to  the  peUicle  beneath  the  longer,  aerial  hyphae. 
They  are  dark  oUvaceus  imder  the  microscope.  The  medium  becomes 
darker  as  the  fungus  develops  upon  it. 

On  steamed  potato  slants.  Growth  vigorous.  A  white,  downy,  aerial 
myceUimi  is  first  produced  becoming  a  dirty  greenish  gray  with  age.  A 
peUicle  is  formed  upon  the  surface  of  the  slant  and  may  be  flesh  colored 
or  greenish,  becoming  black  with  age.  FinaUy  the  aerial  myceUum  usually 
collapses,  and  only  a  black,  shining  peUicle  is  observed.  After  growth 
has  entirely  ceased  the  plugs  no  longer  react  for  starch  with  iodine  but 
give  a  good  test  for  reducing  sugar  with  FehUng's  solution. 

On  beet  agar.  Growth  vigorous.  An  aerial,  downy  myceUum  is  first 
produced  which  is  gray-white  becoming  greenish  and  finally  black  with 
age.  Cultures  have  a  sooty,  granular  surface  punctuated  with  whitish 
hyphae  in  scanty  tufts  and  occurring  singly.  The  aerial  myceUum  may 
or  may  not  be  somewhat  zonate.  Spores  are  inclined  to  be  smaller  and 
decidedly  darker  than  those  found  on  other  media,  being  oUvaceus  to 
fuUgineus  imder  the  microscope. 

On  steamed  cherry  twigs.  Growth  vigorous.  A  copious,  downy,  aerial, 
white  myceUum  is  first  produced  which  becomes  a  dirty  greenish  gray 
to  black  with  age,  giving  the  cut  siufaces  a  sooty  appearance.     The  bark 


194  Phytopathology  [Vol.  7 

ifl  Hpareoly  covered.  Spores  are  proiluced  in  abundance  close  to  the  nit 
surfacen  of  the  twif^.  The}'  are  somewhat  smaller  than  thoee  on  vmriouf 
other  media  and  are  dark  olivaceus  to  fuligineus  under  the  microscope. 

On  nat^el  oranges  (Sterilized  by  washing  the  surface  with  mercuric 
chloride  solution).  When  inoculate<l  in  moist  chambers  at  the  navel 
end  a  black  rot  of  the  rag  or  pulp  cells  results  which  is  identical  with  that 
produced  by  Altemaria  Citri  Pierce  (fig.  2).  At  the  point  of  inoculatioii 
an  aerial  mycelium  develops  which  Ls  pulvinate  and  gray-white  at  firat, 
becoming  a  dirty  greenish  gray  with  age.  The  rind  discolors  becoming 
olivaceus  in  a  gradually  increasing  area  around  the  fungus  colony.  Se\'eral 
months  after  inoculation  the  aerial  mycelium,  having  overrun  the  oranf^, 
bleaches  out  and  ultimately  l)ecomes  a  l)eautiful  pink.  The  whole  fruit 
gradually  settles  down  with  a  soft,  moLst  rot. 

On  +  5  nutrient  agar  agar.  This  medium  remains  liquid  due  to  the  high 
acid  content.  The  i.solated  colonies  of  ai'rial  mycelium  are  whitbth  at 
first  l)eroming  s<M)ty  black  with  age  and  rounded  or  hemispherical.  On 
titrating  the  incdiuin  thn*e  ww'ks  after  planting  it  wiis  found  to  have  lieen 
re<luc€»d  to  -f  4.  The  color  was  changed  from  a  light  amlKT  to  a  <leep 
l)rown  (fuligineas).  This  destruction  of  acid  by  the  fungus  was  oliserved 
on  various  other  media.     The  average  of  four  titrations  was  alwa>'s  taken. 

In  genertil  it  was  ol)s<Tved  that  tlu*  color,  shape  and  size  of  the  spores 
pnMluce<i  on  various  me<lia  may  var>'  slightly,  but  the  most  important 
characteristics  n*niain   the  same. 

The  fungim  l)ears  a  striking  similarity  to  Altemaria  Citri  Pierce  and  e\Tn 
a  closer  n^lation-^hip  to  an  Altemaria  found  on  watermelon  leaves.  Purr 
cultun»s  of  the  thn»<»  fungi  wen*  obtained  by  the  single-spore  methoii. 
In  drop  rultun^s  of  4-2  nutrient  broth  the  fungi  may  \h*  said  to  l>e  ich^ntird 
morphologically.  Possibly  the  spon*s  of  A.  Citri  are  slightly  rougher  than 
those*  of  the  other  two,  but  this  difTerenc(*  was  not  found  to  \)o  amslsmi. 
The  thn*<*  fungi  <'antiot  Im*  difTen*ntiate<i  on  nutri(*nt  and  non-nutrim 
agar,  and  tlu*  nits  (inxhu'cd  by  them  in  navel  orang(*s  an*  identical. 

The  cherry  .Xltcniaria  cannot  Ih»  distinguished  from  the  wateniH*lo' 
.Mterniiria  on  -f-'>  nutrient  agar,  but  is  di.stinguished  from  A,  (^htri  c: 
this  medium.  The  latter  jmMhK'es  colonies  which  an*  circular,  whiti^ 
at  tir>t.  iNM-oiiiing  gray  with  age.  They  an*  also  flat  or  depn*ss<H|  wi 
erater-like  e<*nters  which  an*  darker  in  color  (gri.sc*us-oIiva«»us). 

The  cherry  .Mternaria  is  distinguishtMi  fn»m  the  oth€*r  two  Altenia 
when  inoculated  on  <*herrv  leaves  only  by  the  size  of  the  spots  and  t 
rajudity    uith    wliitli    they    an*    produ<*e<l.     The    watermelon  Altenia 
priM|im»s  the  >nialle>t  >|M)ts.  and  they  lievelop  nion*  slowly,  but  the  tl 
fen'MH'  is  very  slight.     Over  four  <lozeii  ino<*ulations  wen*  made  with 
(Vri  and  the  watermelon   .Mternaria. 


1917] 


Rudolph:  Leaf-Spot  Disease  op  Cherry 


195 


The  cherry  Altemaria  was  distinguished  from  the  other  two  by  its  ac- 
tion on  watermelon  leaves  (var.  Cuban  Queen),  being  the  least  virulent 
of  the  three  fungi.  Sixteen  inoculations  each  were  made  with  the  cherry 
Altemaria  and  A .  Ciiri  on  separate  plants.  Twenty-four  inoculations  were 
made  with  the  watermelon  Altemaria  on  a  third  plant.  The  black  spots 
produced  were  identical,  but  the  watermelon  Altemaria  spread  to  the  stem, 
killing  the  plant,  while  the  cherry  Altemaria  confined  itself  to  the  leaves. 
A.  Citri  formed  sUghtly  larger  spots  than  the  cherry  Altemaria  but  also 
confined  itself  to  the  leaves. 

The  cherry  Altemaria  may  be  further  distinguished  from  the  other 
two  in  the  matter  of  spore  germination.    Fresh  spores  of  the  cherry  Alter- 


FiG.  3.  Sporophores  and  Spores  of  Alternaria  Cithi  var.  Cerasi 
From  drop  culture  of  4-  2  beef  broth  with  peptone.     X  500 

naria  will  germinate  in  neutral,  +1,  and  +2  broth  in  less  than  twenty- 
four  hours,  but  in  +7,  and  +8  broth  germination  rarely  takes  place  in 
less  than  a  week.  It  will  grow  and  produce  spores  in  +8  nutrient  broth. 
Spores  of  the  watermelon  Alternaria  will  germinate  in  +8  broth  and  grow 
feebly,  but  the  fungus  has  rarely  been  observed  to  produce  spores  in  this 
medium.  Spores  of  neither  will  germinate  in  +9  broth.  A,  Citri  will 
grow  and  produce  spores  in  +6  broth,  but  spores  will  not  germinate  in 
+7  broth.  Spores  of  both  the  cherry  and  watermelon  Alternarias  ger- 
minate in  +7  and  +8  broth  with  the  greatest  difficulty,  the  germ-tubes 
developing  in  an  abnormal  manner  and  resemble  the  budding  of  yeast. 
Ordinarily  the  germ  tubes  are  straight  with  but  few  septa,  but  in  broths 
of  high  acidity,  the  opposite  is  the  rule. 


196  Phytopathology  (Vol.  7 

The  cherry  Altemaria  cannot  be  distinii^ished  from  the  others  by 
fcprmination  testo  in  alkali  solutions.  All  germinate  readily  in  tap  water 
containing  8  per  cent  normal  alkali  (sodium  hydroxid),  but  in  —10  tap 
water  germination  may  not  take  place  for  a  week.  None  of  the  three 
fungi  will  germinate  in  — 11  tap  water. 

On  steamed  rice  the  watermelon  Altemaria  colors  the  rice  ipiuns  a 
riightly  lighter  shade  of  yellow  than  does  the  cherry  Altemaria,  while 
A.  Citn  colors  them  all  shades  of  yellow  to  laterieious.  In  other  respect* 
the  fungi  arc  identical  on  this  medium. 

On  +5  nutrient  agar  the  growth  and  acid  destmction  by  the  cherry 
Altemaria  was  identical  with  that  of  the  watermelon  Altemaria.    A 
Citri  within  the  same  time  only  reduced  the  acid  content  0.6  per  cent 
instea<l  of  1  per  cent. 

Tlie  longevity  of  the  cherr>'  Altemaria  is  largely  dependent  upon  the 
presence  of  moi.sture.  However,  sports  ov(»r  fourteen  months  old  pro- 
ducer! on  steamed  cherr\'  twigs,  which  drie<l  out  soon  after  the  planting 
of  the  fungus  on  them,  wen*  found  to  l>e  viable,  although  germination 
rarely  Vnyk  [)laoe  in  less  than  a  we<»k  in  neutml  or  +1  broth. 

The  various  (»xix»riments  enumerated  show  the  three  fungi  to  lie  very 
closelv  n»Iated.  The  nanie  of  the  watennelon  Altemaria  is  not  known, 
but  it  is  not  lx*lieved  to  Ix*  .4.  cucurbitce  Ia'X.  which  is  also  parasitic  on 
melon  vines.  The  spon»s  of  A.  ciicurbita'  arc*  descril)ed  as  longer  and 
narn)wer  -mostly  (>()  to  i\H  by  8  to  9  /i — while  the  spores  of  this  particular 
Altemari^i  an*  only  U)  to  47  by  0.8  to  15/4. 

The  ch<»rrv  .\ltemaria  is  not  In'lieved  to  Ih»  the  same  as  Altemaria  Certun 
Potebniii  found  at  Kharkov,  Russia,  the  si>on's  of  that  fungus  l)eing  dc^ 
cide<lly  larger  and  pnMluced  in  v(4vety  patclu*s  on  dr\'  margins  of  leaves, 
a(H*ording  to  Saccardo. 

Believing  this  fungus  to  U'  hitherto  undesrrilMMl.  and  being  of  the  opinion 
that  its  rIoM'  relationship  to  A.  Citri  Piera*  entith's  it  to  l)e  elassificMi  as 
a  variety  of  that  s|M»('ies  the  writ(»r  suggi*sts  the  name  Altemaria  (^itri 
Pierce,  variety  Cvrasi  with  the  following  technical  description. 

Altemaria  Citri  Pierre  var.  Cerasi  nov.  var. 

PrcN luring  <lead  >iMits  on  leaves  of  swe<'t  cherr\'.  Sjxits  2  to  14  mm. 
in  diameter,  n'dtlish  brown  or  chestnut  above  and  lighter  below,  often 
faintly  zonat(%  soni(*times  with  a  distinct,  lighter  <*olore<l  central  area  and 
UMially  ^ta^tinK  from  an  uxm^vX  injury,  sometimes  extending  outward  in 
an  indefinite  nio?^ii<'. 

\  wound  pani>ite  only,  :ls  shown  by  artificial  infections,  capable  of 
pnxluring  s|M)ts  on  leaves  of  numerous  plants.  Distinguished  from  A, 
Citri  PiiTn*  with  difficult  v. 


1917]  Rudolph:  Leaf-Spot  Disease  of  Cherry  197 

Mycelium,  in  leaves  of  sweet  cherries,  sub-epidermal,  of  slender,  sep- 
tate, hyaline  hyphae,  1  to  3  m  in  diameter.  Aerial  mycelium  very  rarely 
produced  and  then  only  in  the  presence  of  unusual  humidity  and  opti- 
mum temperature,  hjrphae  3.4  to  4.8  n  wide,  gray-white  to  pale  oUvaceus, 
long,  silky,  branched,  septate;  conidia,  not  observed  in  field,  occasionally 
produced  in  presence  of  unusual  humidity  and  optimum  temperature — 
then  close  to  the  lower  surface  of  the  leaf,  never  on  long,  aerial  hyphae, 
clavate  fusiform  or  elUptical  at  maturity,  16.3  to  57.8  by  6.8  to  15.3  /*,  muri- 
form,  translucent,  oUvaceus-brown,  slightly  verrucose  or  smooth,  becoming 
constricted  at  the  septa  with  age,  transverse  septa  commonly  parallel, 
3.3  to  9.9  fjL  apart,  with  short,  smooth,  hyaline-subhyaline  isthmus  which 
is  usually  3.4  by  3.4  /x;  several  catenulate,  in  cultures  2  to  7  in  simple  or 
branched  series,  somewhat  variable  in  size,  form  and  color,  germination 
from  any  cell,  produced  abundantly  on  various  cultiu^  media.  Conidio- 
phores,  short,  in  cultures  1.7  to  153  /*  by  1.7  to  6.8  m,  olivaceus-subhyaline, 
erect,  in  general  narrower  than  the  vegetative  hyphae. 

Bureau  of  Plant  Industry 
Washington,  D.  C. 


BLISTKU  SPOT  OF  APPLES  AND  ITS  RELATION   TO  A 

DISEASE  OF  APPLE  BARK 

Dean    H.    R  o  b  e^ 

With  Three  Ficjureh  in  the  Text 

In  the  present  pufXT  is  descrilx'd  a  (ILseaHe  of  apples  (fruits)  which  hit 
\KH*n  under  investigation  through  two  {^rowing  seasons.  A  brief  report 
has  already  l)een  published  by  the  writer^  but  so  far  no  other  mentioa  df 
it  luis  l)een  found  in  the  literature.  There  is  fqven  also  a  descriptaoil  cf  a 
dis(*aseof  apple  bark  which  seems  to  l)e  causally  rt^ated  to  the  fruit 
The  ex|)eriinental  pr(K)f  is  not  yet  complete  but  considerable 
that  the  relation  actually  exists  has  l>een  obtained  and  will  be  found 
marized  in  the  s<»c()nd  part  of  the  papt»r. 

BLISTKK   SPOT   OF   APPLEH 

Occurrence  ntul  general  apiHtarance  of  the  disease 

The  blister-s|)<>t  dis<*:i.se  was  first  noticed  on  July  6,  1915,  on  Noifoft 
Pcauty  (dwarf)  as  roughly  (*ircular  or  sometimes  irregularly  lol)ed  shallow 
blisters,  varying  in  color  from  light  brown  to  black,  and  in  siie  from  1  lo 
r>  mm.  in  diameter  (average  aUmt  2  mm.)  by  0.2  mm.  in  depth.  Searrh 
through  the  experiment  station  orchard  at  Mountain  (irove,  Miiwtmri. 
thru  .showed  similar  .s|K)ts  on  Melon,  Ishewold,  and  Hawley.  In  1916 
s(>ots  wen'  first  found  aUxit  the  mid<lle  of  June  on  Blue  Peamiain,  Higfnn- 
Iwitham,  Yellow  Transparent,  Ii<'noni,  Melon,  Hock  Pippin,  I^Ansingburg. 
Karly  Hi|M*.  Victuals  and  Drink.  Isham,  Ishewold,  Hawley.  Norfolk 
Hcauty,  Hr<l  Astrachan,  White  Pippin  (wrongly  given  as  Yellow  Xewt4»n 
ui  the  rc|N>rt  mentioned  earlier).*  Kloiidyke,  Duling,  ami  Jonathan.  AHow- 
in^  for  the  fact  that  .su<*h  varieties  as  Yellow  Tran.^^pan'nt  and  Ke<l  .VMra- 
rliari  wen'  goiu'  when  afTe<*ted  apples  wen*  di.scovere<l  in  191o.  this  list 
'Hhow>  the  diseasi'  much  mon*  prevalent  in  the  station  orclianl  in  19IH 
tliaii  m  P.M.').     Little  is  known  of  its  distribution.     .\ppU»s  showing  typi- 

'  The  writiT  v%i>lirH  to  HrkiKiwIcd^c  hi**  iii«l('l>t4'<hirf(«4  to  Mr.  IlHTold  Swartimt  and 
.\Iij»?»  n«';itrir«'  W  liifc.  uithoiit  u  ho*ti>  <:in'ful  :iii(l  i*rtiri«*fit  hflp  thr  work  hrrr  rr- 
|»«irt«Mi  roiiM  rio*  have  iMM'ti  :l^^oIl)pli^h4■<l  m  [\\v  tunc  HVailjihlr. 

'  Ho>M'.   I)«';iii  II       llliHti-r  >in»t  of  :ippl««'»     ;i!i?*tr:irt   .     Phytopath.  6:   II0      Krh 
P»|ti. 


200  Phytopathology  [Vol.  7 

appearance  dcscrilxHl  above  (fig.  i,  B).  On  white  or  yellow  apples  such 
as  Yellow  Transparent  the  spots  are  surrounded  by  a  narrow  greenish 
ring;  the  same  ring  is  found  on  Benoni  and  Duling,  which  are  red  when 
ripe,  but  the  spots  on  Red  Astrachan  show  a  red  ring. 

The  disease  is  not  a  serious  one  in  the  way  that  bitter  rot  is  serious. 
Nevertheless,  susceptible  varieties  often  have  the  whole  crop  so  seriously 
blemished  as  to  be  unfit  for  packing  in  any  but  the  lower  commercial 
grades.  P'ortunately  such  severe  injur>'  seems  to  be  confined  to  varieties 
of  minor  commercial  importance. 

Cause  of  the  disease 

The  disease  is  caused  by  an  organism  l)elonging  to  the  genus  Piieudo- 
monas.  It  does  not  seem  to  have  been  descrilx^d  previously  and  the 
following  name  is  propo8e<l  and  a  description  appended: 

Pseudomonas  papulans  n.  sp. 

Morphological  characteristicji.  The  organism  Ls  a  rod,  motile  by  one 
to  six  polar  flagella.  Fiagolla  occur  at  lx)th  poles  and  were  demonstrated 
by  means  of  Ixx'ffliT^s  flngclla  stain,  using  stains  on  Pseudomonas  fiuart^ 
cens  as  check.  (Px.  fluorescena  fumisheil  by  the  American  Museum  of 
Natunil  History',  New  York).  Staine<l  from  twenty-four-hours-old 
agar  cultun's  the  organism  shows  as  a  short  ro<l  with  rounded  ends,  meas- 
uring 0.9  to  2.3  M  lofif^.  by  about  0.()  ^i  in  diameter.  It  occiu«  singly  and 
ver>'  often  in  pairs.  No  si>ores  or  caj)sul(»s  have  lx»en  \lemon8trat4*d.  It 
stains  n*adily  with  carbol  fuchsin,  gentian  violet,  and  methylene  blue. 
It  is  not  acid  fast  and  it  den's  not  .stain  bv  (iram. 

Cultural  characterii<tia<.  The  following  account  is  base<l  on  a  study  of 
25  stniins  of  the  organL^m  isolatc<l  from  (1)  naturally  infectetl  sp«»ls. 
(2;  artificial  infections,  and  (3)  infect ioas  pnxluced  with  the  n«iM>late<i 
organism.  Culture's  wen*  coinpanMl  with  li.  coli  and  B.  amyUnporus  (fur- 
nished I IV  the  .\iucrican  Mummhii  of  Natural  Hi.stor\',  New  York). 

Thr  organism  does  not  form  gas  from  |)eptonized  Inmillon  containinn 
dcxtniM*.  sn(M*haros4\  nialtos<'.  hu'tose.  glycerin,  or  maiHiit,  and  it  d<M»!* 
not  rl<Mi<l  the  cl<KS(*d  rnd  of  th<'  fcrmrntation  tuU*  in  any  case.  (tn>wth 
sto|h«  short  in  thr  neck  of  the  tulM*.  indicating  an  obligate  aerolM.\  The 
oric:int>tii  clouds  lM*<*f  bouillon  -h  H).  slightly  in  twenty-four  hours,  and 
nHMJiTatrly  in  forty-«'ight  hours.  It  li(|U(*fics  gelatin  slowly  at  20^1  \. 
li(|uefa<*tion  not  U^ing  complete*  in  test-tuiN*  cultun^s  until  after  twel\*e 
to  fourtn'ii  w<H*ks.  Some  >t rains  form  a  soft  (*oagulum  in  plain  milk. 
S4»ine  no  roaguluni  at  all.  but  all  of  thiMu  clear  it  in  alnmt  twenty  ila\'ii. 
The  organism  blues  litmu>  milk  throughout   <luring  the  first  six  day». 


1917]  Rose:  Blister  Spot  of  Apples  201 

with  the  formation  usually  of  a  soft  coagulum,  and  then  gradually  decolor- 
izes it  from  above,  with  the  production  of  a  dark  blue*  color  thr9Ugh- 
out  after  sixteen  to  twenty  days.  On  plain  agar  it  produces  a  filiform, 
slightly  convex,  whitish  growth.  On  potato  cylinders  it  produces,  after 
forty-eight  hours,  a  whitish,  filiform,  irregularly  spreading  growth,  which 
after  seven  days  shows  a  sUght  browning,  accompanied  by  a  sUght  darken- 
ing of  the  mediimi.  The  optimuip  temperature  seems  to  lie  between  25® 
to  28*^C.,  though  fairly  good  growth  takes  place  at  20*^C.  It  does  not 
grow  at  37°C.  The  thermal  death-point  has  not  been  determined.  On 
dpxtrose  agar  and  glycerin  agar  the  organism  produces  a  light  green  fluores- 
cence as  also  in  Uschinsky's  and  asparagin  solutions,  but  it  does  not  grow 
in  Cohn's  solution.  A  test  with  six  strains  showed  that  the  organism 
grows  in  bouillon  over  chloroform  and  tolerates  hydrochloric  acid  up  to 
+  15  on  Fuller's  scale,  and  sodimn  hydroxide  to  —5.  The  optimmn  re- 
action for  growth  seems  to  be  about  +10. 

The  organism  is  sensitive  to  sunUght.  Petri  dishes  one-half  covered 
with  black  paper  and  exposed  to  sunlight,  on  August  3,  on  a  bag  of  crushed 
ice  showed,  for  six  strains,  an  average  of  98  per  cent  killed  after  an  exposure 
of  ten  minutes.  Six  strains  inoculated  into  test-tubes  containing  different 
amounts  of  sodium  chloride  showed  growth  in  all  up  to  and  including 
4  per  cent.  Using  the  method  described  by  Edson  and  Carpenter*  it 
was  found  that  the  organism,  produces  alkaU  in  plain  milk  during  the  first 
ten  days,  then  increasing  amounts  of  acid  up  to  forty  days.  On  peptonized 
bouillon  containing  two  per  cent  of  various  sugars  and  alcohols  it  produces 
acid  from  dextrose  and  saccharose,  alkaU  from  lactose,  and  maltose,  and 
neither  acid  nor  alkali  from  glycerin  or  mannit. 

Quick  tests  for  differential  purposes;  bluing  of  litmus  milk  followed  by 
decolorization  from  bottom  upward  accompanied  by  slow  digestion  and 
the  formation  usually  of  a  soft  coagulum;  fluorescence  and  luxuriant  rugose 
growth  on  glycerin  agar;  fluorescence  on  neutral  gelatine  but  none  on  gela- 
tine +  10. 

Isolation  of  the  organism.  The  organism  was  easily  isolated  from  affected 
apples  by  the  method  of  poured  agar  plates.  Spotfe  were  merely  given 
a  good  washing  with  steriUzed,  distilled  water,  sometimes  preceded  by  a 
brief  rubbing  with  a  finger  dipped  in  alcohol.  The  diseased  material  was 
then  scraped  off  with  a  sterilized  scalpel  and  dropped  directly  into  melted 
agar.  The  colonies  appeared  in  from  thirty-six  to  forty-eight  hours, 
usually  in  pure  culture.     They  were  thin,  smooth,  circular,  glistening, 

•  Saccardo,  P.  A.    Chromotaxia  seu  Nomenclator  Colorum.    1-22.    2  pi.    Pata 
vii,  1894. 

*  Edson,  H.  A.  and  Carpenter,  C.  VV.  Micro-organisms  of  maple  sap.  Vermont 
Agr.  Exp.  Sta.  Bui.  167:  321-610.    1912. 


2()2  Phytopathology  [Vol.  7 

whitish  by  n^flerted  liRht,  bluish  by  transinitted  liRht,  and  0.1  to  l.U 
mm.  in  diameter.  Not  all  the  affected  varieties  were  used  in  thia  work 
but  no  difficulty  was  experienced  in  obtaining  pure  cultures  from  thoete 
that  were  usetl. 

Inoculation,  l^in^  sul>-cultures  from  single  colonies,  the  disease  hah 
l>een  repro<luced  on  six  varieties  of  apples.  In  this  work  123  apples  were 
use<l,  60  of  which  were  che<*ks.  All  of  them  were  treated  cm  the  trees 
and  were  bagfced  after  treatment.  The  incubation  period  averaised  about 
fourteen  days,  thouf^h  some  apples  failed  to  show  signs  of  the  disease 
until  the  end  of  eif^hteen  to  twenty-five  days.  Some  strains  of  the  orfcanisin 
were  infectious  on  all  the  varieti(»s  teste<l,  others  on  only  one  or  two. 
Further  work  is  nc<*essar>'  to  clear  up  this  situation. 

Inoculations  wen*  made  in  thret^  different  ways,  using  twenty-four  to 
fort y-t»ight -hours-old  iKuiillon  cultun»s: 

1.  By  spniying  uninjunnl  apples  with  th<'  bouillon  culture.  No  info^ 
tion  n*sulted. 

2.  By  spraying  apples  whi(*li  had  first  Innm  pricked  with  a  flamed  needle. 
Seventy-two  |kt  cent  infection  resulted  on  Yellow  Transparent,  Jonmthan, 
Melon,  Hawley.  and  White  Pippin.  No  signs  of  infection  appeared  on 
I^*noni. 

3.  By  hy|KMlennic  inje<*tion  just  under  the  epidermis.  Eighty  per 
e<>nt  infection  resulted  on  Benoni,  Hawley,  Jonathan,  Melon,  and  White 
Pippin. 

Ino(*ulations  with  n*isolat4Ml  (uiltun's  by  hyixKiermic  injection  on  ^liite 
I^ppin,  Jonathan,  and  Melon  wen>  also  successful.  The  organism  isolated 
from  infections  agn>ed  in  all  characteristic's,  morphological  and  eultural, 
with  the  one  us(mI  for  ino<*ulation.  Checks  to  correspond  with  the  three 
methods  of  inoiHilation  descrilM'd  al>ove  nnnaineii  healthy  throughout 
tlu*  s(*ason. 

KorcSII-HARK   OK    SC'CKFY-HAKK    (WNKEK   OP  APPLBS 

DeAcriptitm  of  the  f{ij<ease 

What  might  U*  called  tlu*  ({uiescent  st:tge  of  the  scurfy-lmrk  disease 
<M*rurs  :us  patches  of  n>ughen<Ml  scaly  bark  which  simiewhat  respmhie 
blotch  ranker  {PhyUostictti  suUtnrin  K.  and  Kj.  but  differ  fmm  it  in  show- 
ing no  blotrh  pycnidia  and  usually  no  regularity  of  cracking  up  and  down 
or  arri»NS  X\\v  limb  (fig.  2.  .1).  Thes<*  roughened  |):itch(*s  var>'  gn*atly  m 
M/e  fn»ni  tliosi'  covering  only  a  few  sipiare  centimeters  to  thost*  covering 
till*  wliolf  Hjdt'  nf  a  limb  for  a  meter  or  in<»re.  Thev  an*  usuallv  f(»und  i»n 
thf  iiurth  ^ide  of  a  limb  and  with  few  exceptions  an*  bordenNi  by  a  pimpltMl 


1917]  Rose:  Blister  Spot  of  Apples  205 

scaling  off  of  small  patches  without  the  formation  of  a  definite  spongy 
layer.  Sometimes  the  diy,  brown  vestiges  of  such  a  layer  can  be  foimd, 
sometimes  not.  Possibly  in  such  cases  it  develops  slowly  and  progres- 
sively from  one  point  to  another,  loosening  the  bark  only  a  little  at  a 
time  and  drying  down  almost  immediately. 

No  detailed  studies  of  the  diseased  tissues  have  been  made.  A  pre- 
liminary survey  of  both  free-hand  and  microtome  sections  shows  the  pres- 
ence of  peculiar  spots  or  pustules  like  those  described  by  Hewitt*  in  his 
work  with  a  new  disease  of  apple  bark  in  Arkansas  and  by  the  writer* 
in  work  with  what  is  almost  certainly  the  same  disease,  known  at  this 
Station  for  over  ten  years  under  the  name  of  pimple  canker.  It  remains 
to  be  proved,  however,  whether  this  disease  is  a  phase  of  or  in  any  way 
lielated  to  the  true  scurfy  bark  canker.  The  most  that  can  be  said  at 
fvesent  is  that  they  show  considerable  morphological  similarity  and  are 
often  though  not  always  associated  on  the  same  tree. 

Besides  the  deep-peeling  type  of  scurfy-bark  canker  there  sometimes 
occurs  a  "shallow-peeling*'  type,  in  which  only  the  epidermis  is  loosened. 
A  spongy  layer  is  formed  here  also,  but  it  is  thinner  and  more  evanescent 
tiian  in  the  deep-peeling  type. 

Occurrence  of  the  disease 

The  disease  occure  on  such  standard  varieties  as  Ben  Davis,  Jonathan, 
Logan,  White  Winter  Pearmain,  Beach,  Stayman  W'inesap,  Munson, 
and  Marsh,  but  much  more  severely  on  certain  dw^arf  varieties. 

The  writer  has  found  the  disease  in  numerous  orchards  in  southern 
Missouri  and  has  received  specimens  of  it  from  perhaps  a  dozen  localities 
scattered  over  the  state.  No  information  is  at  hand  as  to  is  occurrence 
in  other  states,  unless  the  trouble  investigated  by  Hewitt  in  Arkansas  be 
considered  a  phase  of  it.  Affected  trees  are  not  quickly  killed  as  in  the 
case  of  Illinois  canker — caused  by  Numviularia  discreta — but  there  is  no 
doubt  that  the  peeling  off  of  fresh  layers  of  bark  every  spring  is  definitely 
injurious  to  the  tree,  aside  from  the  opportunity  given  for  entrance  of 
canker  fungi  and  various  bark  insects. 

Cause  of  the  disease 

The  disease  seems  to  be  caused  by  the  same  organism  as  that  of  the 
fruit  spot.     Poured  agar  plates,  using  material  from  (1)  the  deep  lying 

*  Hewitt,  J.  Lee.  An  unknown  apple  disease.  Arkansas  Exp.  Sta.  Bui.  122: 
481-491.     1912. 

•  Rose,  Dean  H.  Report  of  the  Pathologist.  Missouri  State  Fruit  Exp.  Sta. 
Rept.    1913-14  (Bui.  24):  30.    1914. 


206  Phytopathology  f\*OL.  7 

spoDfor  layer,  (2)  the  pimply  ridge  at  the  edge  of  roughened  areas,  (3) 
areas  exposed  naturally  the  preceding  season  when  the  loosened  layer 
peeled  off,  (4)  the  spongy  layer  under  loosened  epidermis,  gave  pra<rtically 
'pure  cultures  of  an  organism  very  similar,  morphologically,  to  the  blister- 
spot  organism.  Extensive  cultural  studies  show,  however,  that  instead 
of  one  organism  there  are  two  different  ones  or  possibly  two  closely  related 
but  distinct  varieties.  One  of  them,  represented  by  five  strains,  shows 
great  similarity  in  morphological  and  cultural  characteristics  to  the  bliiH 
ter-spot  organism;  the  other,  represented  by  fifteen  strains,  resembles 
the  blister-spot  organism  morphologically  but  differs  from  it  in  cultural 
characteristics.  It  liquefies  gelatin  rather  rapidly,  it  produces  a  green 
fluorescence  on  nutrient  agar  and  it  begins  to  clear  litmus  milk  inside  of 
twenty-four  to  thirty-six  hours.  The  first  and  second  of  these  are  not 
characteristic  of  the  blLster-spot  organism,  while  the  last  is  characteristic 
only  of  three  strains. 

Inoculations 

Inoculation  of  bark  with  the  rapidly  liquefying  bark  organism  produced 
swollen  spots  1  to  2  mm.  high  and  covering  an  area  of  roughly  1  sq.  cm. 
(fig.  3,  C).  At  these  swellings  the  typical  signs  of  the  disease  were  re- 
produced, in  miniature,  and  an  organism  was  recovered  which  agreed 
in  cultural  and  mor|)hol(>giral  characteristics  with  the  one  use<l  for  inocula- 
tion. The  check.s  showed  only  a  slight  swelling.  Typical  blister  spots 
on  the  fruit  wen*  pnxiuced  by  inoculating  Jonathan  and  Melon  apples 
with  l)oth  bark  organisms  and  these  in  turn  were  recovere<l  fr«>m  the 
lesions  pr<Hluce<l.  While  such  evidence  is  strongly  suggestive  it  is  not 
final  pnK)f,  an<l  nion*  work  is  nec<\ssar>'  l)ef()re  the  true  relation  U»tween 
th«  fruit  di.s<»jLS<»  and  the  bark  di.*^»jis<»  can  Ih»  dis«rovenHl. 

In  table  1  arc?  shown  the  results  of  compamtive  tests  made  with  the 
blLster-s|>ot  organism  and  the  rapidly  li(|U(*fying  bark  organism. 

A  similar  comi)arison  lM*tw<H*n  the  bark  and*  the  blister-spot  organL^n 
on  the  onr  hand  an<l  pHcudomorum  fluorescent  on  the  other  .show  s<i  many 
<liffrrrnei»s  that  the  two  fonner  must  Ik»  considrn»d  entin»lv  distinct  fn>m 
the  latter. 

Further  work  on  these  <iLs<':i.ses  should  include  (Da  continuation  of 
cultunil  studi(*s  of  the  blister-s|H)t  organism  and  the  two  bark  organbuiut. 
(2;  (To>s-incMnihitions  from  bark  to  fniit  and  from  fniit  to  l>ark,  uii  a 
study  of  the  time  and  nxxle  of  infection  and  (4)  a  study  of  the  microscopi- 
cal eli:iraeteri>tirs  of  health v  and  <lis<»as«Ml  tissues. 


I 


1917] 


Rose:  Blister  Spot  op  Apples 


207 


TABLE  1 
Comparison  of  the  blister-spot  organism  and  the  bark  organism 


Agar  plates. . 

Agar  slant. . . 
+  10  bouillon 

Gelatin  stab . 


Neutral  gelatin  stab., 


Litmus  milk 


Sterile  milk. 


Glycerin  agar. 


Uschinsky's  solution. 


Nitrate  reduction 

Indol  test 

Ammonia  test 


Resistance  to  sunlight. 


Flagella. 


BLr8TKB-«POT  OBOAKISM* 


Whitish  colonies,  slightly 
bluish  in  transmitted 
light  ;  medium  not 
greened 

Growth  rather  slow,  no 
fluorescence 

Clouding  and  pellicle;  one 
strain  showed  faint  green 
fluorescence  in  2  weeks 

Liquefaction  slow,  begins 
in  2-3  days.  Complete 
in  12-14  weeks.  No  fluo- 
rescence 

Liquefaction  slow.  Slight 
fluorescence 

Alkaline  reaction  for  10 
days,  then  slow  increase 
in  acidity  up  to  40  days. 
Medium  cleared  in  2-3 
weeks;  final  color  blue 
throughout.  Banded 

appearance  produced  by 
3  strains 

Clearing  begins  in  from  7- 
10  days,  complete  in  17- 
20  days 

Growth  vigorous,  elevated, 
contoured  to  rugose. 
Moderate  fluorescence 


Clouding  moderate;  bluish 
green  fluorescence.  Pel- 
licle of  pseudo-zoogleae- 
like  fragments 

None 

No  indol  in  20  days 

Ammonia  produced 


Average  of  98  per  cent 
killed  after  10  minutes 
exposure 

Bipolar;  one  to  several 


BABK  OBOAmSIC* 


Whitish  colonies,  slightly 
bluish  in  transmitted 
light;  medium  slightly 
greened 

Growth  rather  slow,  fluo- 
rescence marked 

Clouding;  green  fluores- 
cence after  1  week;  four 
strains  showed  pellicle 

Liquefaction  more  rapid, 
begins  in  24  hours,  com- 
plete in  2  months.  Slight 
fluorescence  after  1  week 

Liquefaction  more  rapid. 
Marked  fluorescence 

Slight  alkaline  reaction  at 
top  in  2  days,  acid  reaction 
below.  Acidity  increases 
as  digestion  proceeds. 
Banded  appearance  re- 
sulting in  clearing  in  3-4 
weeks.  Final  color  green- 
ish blue  above,  buff  below 

Clearing  begins  in  36  hours, 
complete  in  3-4  weeks. 
Green     fluorescence 

Growth  vigorous,  elevated, 
contoured  to  rugose. 
Fluorescence  more 
marked  than  for  blister- 
spot  organism 

Same  as  for  blister-spot 
organism  except  fluores- 
cence more  marked  with 
some  strains 

None 

Indol  present  in  10  days 

More  ammonia  produced 
than  by  the  blister-spot 
organism 

Average  of  50  per  cent 
killed  after  10  minutes 
exposure 

Bipolar;  one  to  several 


^  Under  this  heading  are  included  also  the  slow  liqueflers  from  bark. 
*  Under  this  heading  are  included  only  the  rapid  liqueflers  from  bark. 


208  Phytopathology  (Vol.  7 


METHODS   AND   MKDIA 

As  standanls  for  methods  liiid  for  the  making  of  media  the  writer  has 
followed  directions  given  in  Krwin  V.  Smith's  Raeteria  in  Relation  to 
Plant  Diseases,  Vol.  I,  and  ICyre's  Ha<*teriolo|dnil  Teehnie,  2nd  Kd.. 
except  where  noted  otherwise  in  the  t(»xt. 

Sl'MMAKY 

1.  In  tlie  foregoing  i)a|K»r  is  d(\scrilHMl  a  l)aeterial  disease  of  applf>. 
no  mention  of  w)ii<*h  has  Ihm'Ii  foim<i  in  phytopathological  literatunv 

2.  By  isohition,  niltural,  and  inoculation  work,  it  is  proved  that  thbi 
dis<»ase  is  <'aused  l)V  a  motile  organism,  which  H(jueties  gelatin  slowly, 
and  lK»longs  to  the  grccn-fiuorescent    group  of  l)acteria. 

'A.  H<*caus4'  of  the  Mister  spots  produc'(Ml  by  this  orgsmism  on  the  Mir- 
fa<*e  of  apples,  the  naiiH*  Pscmlofunntis  pdjnthins  is  profKwed. 

•I.  Description  is  also  given  of  a  rough-hark  or  scurfy  hark  canki-r 
from  which  has  Im^cii  isolated  an  organism  also  U'longing  to  the  gn-«*n- 
fluoH'Scent  grou)). 

.">.  Kvidence  is  present I'd  that  then*  are  really  two  varieties  of  the  hark 
organism,  one  of  whirh  has  all  of  the  cultural  rharact eristics  of  the  hlister- 
sfxit  organism,  including  s|(»w  Ii(iuefa<*tion  of  gelatin,  while  the  c»ther  dif- 
fers fn»m  it  in  S4'veral  import .iiit  particulars,  including  rather  nipid  li«|Uf>- 
facti(»n  of  gelatin. 

(>.  Inoculation  of  healthy  apple  hark  with  two  strains  of  the  nipi<ily 
lifiuefying  hark  organism  pHxluccd  small  lesions  which  showe<i  the  typi- 
cal <'racking  Ioom*  of  diM*:iM'>  from  healthy  hark,  and  in  sevend  e:is*'s  thf 
lumpy  apjM'arance  characteri>ti<*  of  the  early  stages  of  the  scurfy -tiark 
canker. 

7.  .\n  organism  agrei-ing  in  cultural  react ion>  with  the  one  umhI  fur 
inoculati<»n  has  Imi'Ii  re<*overed  from  thesi*  le>ions. 

S.  Typical  hli>ter  s|)ot>  have  Ihh'Ii  produced  hv  inoculation  of  Imth 
tyjM's  of  hark  organism>  into  healthy  apples.  From  th<^»  s|)ot,s  the  or- 
gani>ms  u>ed  for  inoculation  havi*  U-eii  recov<»nMi. 

\K  \  preliminary  <Mimparative  >tudy  of  the  cultural  chaniet<Tist ii-^  oi 
the  Mi«»ter->pnt  organi*»m  ami  the  two  h.ark  organisms  suggi^ts  tluit  fhf 
difference  iM-twei-n   them   are  difTeren<-e>  of  degn-e  nit  her  than  of   kind 
That  i^.  that  .all  thre<*  are  iM»«»sihly  men-ly  varieties  of  one  s|n»cic»s.      Mon* 
work   i-*  nec4'*.sary.  however.  U^fore  this  <|ue^tion  ni  n  lati<inship  can   U* 

M'ttlrd. 

Mis-^oi  HI  Statk  KiiMr  l*!xPKHiMK\r  Sr\rio\ 

M«>l\rAlN    <IUoVK.    Ml^S4U  KI 


THE  PATHOGENIC  ACTION  OF  RHIZOCTONIA  ON 

POTATO 

H.  T.  GOssow 

With  One  Figure  in  the  Text 

It  appears  that  satisfactory  evidence  has  been  lacking  clearly  demon- 
strating the  pathogenic  action  of  Rhizoctonia  (Cortidum  vagum  B.  &  C.) 
on  various  host  plants,  particularly  the  potato. 

The  attention  which  the  well  known  disease  has  received  in  the  new 
world  and  more  recently  in  the  old,  left,  in  my  opinion  and  in  that  of 
quite  a  number  of  other  investigators,  several  important  points  unex- 
plained. Every  pathologist  fully  recognized  the  symptoms  of  this  dis- 
ease which  have  come  to  be  regarded  as  typical  Rhizoctonia  infection. 
The  unmistakable  folding  of  the  leaves  of  the  growing  plant,  together 
with  the  brown  stem  lesions  so  frequentlj*^  described,  in  other  instances, 
or  in  addition  perhaps,  the  formation  of  aerial  tubers  and  peculiar  small- 
ness  of  subterranean  tubers,  are  now  well  known  as  general  symptoms 
resulting  from  an  attack  of  Rhizoctonia. 

Indeed,  the  folding  of  the  leaves  associated  with  this  disease  differs 
greatly  from  the  curling  of  the  leaves  of  plants  affected  with  leaf  roll, 
particularly  noticeable  is  this  difference  when  examining  the  lower  leaves 
of  an  affected  plant.  Where,  however,  doubt  existed,  the  presence  of 
stem  lesions  was  looked  upon  as  final  proof  of  a  Rhizoctonia  infection. 

I  must  confess,  however,  that  the  often  surprising  scarcity  and  appar- 
ent superficiality  of  these  lesions,  nay,  often  enough  their  entire  absence 
in  what  was  otherwise  unmistakably  a  plant  infected  with  Rhizoctonia 
and  not  with  leaf  roll,  frequently  caused  me  surprise  and  certainly  failed 
to  readily  convince  the  farmers  on  the  occasion  of  field  demonstrations 
of  the  correctness  of  the  diagnosis — which  at  times  I  shared  much  against 
my  own  belief. 

For  some  time  I  have  endeavored  to  discover  the  true  pathogenic  action 
of  this  fungus  on  the  host  plant.  My  colleague,  Drayton,*  demonstrated 
to  my  satisfaction  the  profuse  permeation  of  the  tissues  of  and  surround- 
ing the  lesions,  but  even  that  failed  to  convince  me  entirely  of  the  cause 
of  the  characteristic  symptoms,  which  statement  is  not  intended  to  infer 

^Drayton,  F.  L.  The  Rhizoctonia  lesions  on  potato  stems.  Phytopath.  6:  59. 
1915. 


210  Phytopathology  [Vol.  7 

that  I  (louhtcHl  Rhizoctonia  to  l^e  associated  with  the  same.  But  from 
what  evidence  was  available,  the  actual  injuries  caused  by  the  stem  le- 
sions ^-ere  so  infinitesimal  that  it  was  felt  the  true  injury  is  done  elsewhere, 
and  what  we  did  observe  was  the  result  of  such  unlocate<l  but  far  more 
serious  injury. 

A  careful  stud}'  of  diseased  plants  in  the  field  revealed  at  first  little  or 
no  additional  clues.  Lesions  were  sometimes  present  where  the  lea\*es 
were  folded,  the  tubers  were  covered  with  more  or  less  numerous  lumpy 
funfcous  nuisses,  indeed  the  roots  often  showed  the  well  known  pseudo- 
sclerotia.  Pot  experiments  showed  the  presence  of  sclerotia  on  rootlets 
more  abundantly  th^m  was  the  case  in  the  fiel<l,  and  yet  while  abundiuit 
superficial  and  lesser  amount^s  of  intracellular  h>^hae  of  Rhizoctonia  were 
found  on  microscopical  examination,  the  evidence  of  an  all  round  general 
soundness  of  the  underground  parts  examined  still  left  the  seat  of  the 
injury  undetermine<l. 

On  careful  examination  of  the  root  system  of  a  plant  clearly  affected 
with  Rhizoi*tonia  and  no  other  disease,  that  had  lx*en  pulled  up  from  loose 
sandy  soil,  or  had  l)een  lifted  with  care  by  means  of  a  fork  or  spa<le.  one 
factor  at  last  attracted  my  att<»ntion,  which  later  led  to  interestin^c  oliser- 
vations.  This  was  the  almost  entire  al)sence  of  the  fine  fibrous  rootlets. 
so  common  in  sound  plants.  Surc»ly  such  rootlets  must  have  been  presu 
ent  ori^nally?  When  examininfc  thereafter  plants  in  various  stagi*s  of 
infection  one  could  obstTve  a  corresponding  absence  or  presence  of  finer 
nH)tlets  ucconiing  to  the  amount  of  disease  present.  Of  course,  in  thi* 
detennination  can*  is  net»essiir>',  but  after  some  experience  one  cannot  but 
recogniz<»  the  existing  n^lation  of  nK)tlets  to  deja"ee  of  disease. 

What  if  the  fungus  a<*ted  upon  the  rootsS  of  the  growing  plant  similar 
to  the  way  in  which  it  (1<h's  on  the  r(M)ts  of  Rhizoctonia-infecte<l  tulM^m 
sprouted  in  a  closed  sten<ier  <lish?  The  disastrous  effects  of  the  fungu'^ 
at  the  early  stages  of  growth  arc  sometimes  so  pronounce<l  as  to  kill  off 
growth  liltogether;  this  is  a  H*ell  known  fact. 

Ia'X  us  iM'ar  in  mind  that  in  a  potato  field  we  find  many  stages  of  severity 
of  Hhiz(M*tonia  infection,  from  total  **mi.ssc»s'*  to  one,  two  or  more  shoots 
clearly  afIe<-t<Ml  uj)  to  the  cas4»  wlu^n*  the  plant  Invars  plenty  of  aerial  tulier* 
and  nuMHTous  littU*  |M)tat(M\s  underground  fnnn  which  the  popular  namr 
**littlr  jMitato  (lis<»ji.*<<»"  has  sprung.  .Verial  tul)ers  have  l)een  commonly 
ji.H>ori:iteii  with  Hhizoiioiii:!.  tlu'V  are  jxTluqw  exclu-sively  manufacture«l 
from  in.itrrial  produteil  l»y  the  heaves,  a  <*oinpanitively  slow  proresw,  but 
alua>>  iii(ii(*:itiim  iiiipainMl  nnit  function  in  plants  where  they  may  br 
c<ni>i«h'nM|    abiioriiial.     .Verial    tuU^rs    natunillv    mav    occur    from    anv 

•  •  • 

raii.M*  (MittiiiK  otT  or  intrrnipting  nN>t  function.  Imt  only  when  such  inter- 
nipti(>n>  an*  gradual.     We  have,  then'forr.  no  aerial  tulN*rs  in  the  black 


1917]  Gtjssow:  Rhizoctonia  on  Potato  213 

but  the  roots  infected  with  sclerotia  remain  in  the  ground,  since  they  are 
not  pulled  up  by  the  digger  or  are  at  any  rate  returned  to  the  ground.  With 
the  diminishing  food  supply  in  these  roots,  sclerotia  develop  ready  for 
subsequent  attacks.  This  observation  also  accounts  largely  for  the  soil 
contamination  and  the  persistence  of  the  organism  iQ  land  once  infected. 
It  also  indirectly  suggests  a  new  means  of  control,  viz.,  the  prevention  of 
infection  by  cultural  methods  or  the  application  of  fertiUzers  producing 
vigorous  plants  in  the  first  instance  and  aiding  in  the  production  of  a 
generous  supply  of  new  feeding  roots. 
Central  Experimental  Farms 
Ottawa,  Canada 


212  Phytopathology  [Vol.  7 


leg  disease,  whore  the  cutting  oflF  of  supplien  is  rather  sudden.  .\II  th 
symptoms  are  the  lof^ieal  results  of  the  al)sence  of  the  abundant  fee<linc 
n>ots.  Roots  are  present  in  all  growing  plants,  otherwise  the  planbt 
would  have  died ;  small  and  fine  roots  are  less  in  evidence  in  affecte<I  plant.*< 
while  a  generous  supply  exists  in  healthy  strong  plants. 

De<iuctions — however  logical  they  may  l)e — still  are  h\iM)theses  and 
hypotheses  are  not  facts,  but  the  accompanying  plate  will  pmvi<ie 
some  foundation  for  the  observations  n'corded  and  may  stimulate 
wider  n»s<»arches  on  this  point  than  hiive  l)een  made  so  far.  I  am  satu*- 
fied  fnnn  the  obs<»r\'ations  made,  that  the  destniction — often  ver>'  gradual 
— but  very  jx^rsistent  all  the  same,  of  all  or  many  of  the  feeding  rootj*  of 
the  potato  plant  a<*c()unts  for  every  one  of  the  symptoms  associatcNl  with 
this  dis<»as4».  The  l(»sioiis  which  have  so  often  lH»<'n  recorde<i  are  evident  I  v 
not  of  MTious  conscHiuence,  as  indicated  by  their  general  superficiality  and 
fn»(|uent  (»ntire  al)s<»ncc.  In  some  instan<Ts  iiidcHMl  these  k^icms  an*  not 
due  U>  Hhizortonia  at  all,  but  to  Aciinomya's  scabiej<  (liissow,  whirh  I 
hoiM»  to  sliow  in  anothrr  pa|M»r,  when  they  afford  easy  resting  pl:i(*es  in 
the  unprotecte<l  su|HTficial  cells  for  the  mycelial  m:iss4^  of  I{hiz<N*tonia 
sh(»wn  in  .Mr.  Drayton's  photo-mi<Tographs,  :is  well  as  for  the  [)c*rnie:ition 
of  the  hyphae  into  the  interior,  which,  as  must  have  Imh^ii  noticvd.  is  not 
accompanied  by  any  prominent  injurious  action  ufMm  the  ctIIs  invadtnl. 
A  stu<ly  of  Mr.  Drayton's  slidf»s  clearly  confirms  this  observaticm  :is  well 
as  the  photographs  ma<l<'  fn»m  them  which  an*  ac<rssible  to  our  readers. 

The  i)athogeni(*  a<'ti<»n  is  as  follows:  We  an*  aware  of  the  very  pntfu**** 
growth  (»f  mycelium  of  Hhizo(*tonia.  particularly  in  the  dark,  :u<  al>«»  of 
the  pHNluction  of  enormous  <{uantities  of  ps^'udo-scltTotia  on  nMit>  and 
tuU'rs.  Whethrr  thr  sclcrotia  an*  lt»ft  over  in  the  soil  from  pnM*edinK 
(Mitato  cn)ps  or  c»ther  host  plants,  or  whrther  they  have  Uvn  intnMiu<*«*«i 
by  untn^attMl  infc(*t4Ml  s4»<mI  potat(M*s — (and  what  **farmers'  nm'*  [M»tatm*s 
an*  not  infected?)  <I(m»s  not  matter  much.  Th«»  ti|)s  of  the  fn-sh  nnitlft^ 
niHiU  fall  a  victim  to  tlu*  invading  myc<'lium.  the  nN>t  cap  iH'ing  undoubt«Hlly 
the  nio*«t  vulnerable  |M»iiit  and  s<»on  the  short  nM)ts  have  lN*<*n  d«*>triiye4i. 
the  niyeelium  meanwhile  reaehes  older  rootlets,  whieh  it  mueh  niorv 
ran*lv  de>tro\>.  though  that   hiis  occurn'd.  l)ut   when*  the  mvcelium  fn- 

•  •  • 

(luently  prtHJueo  re^^ting  niyrelial  mas.^<^s  from  which  invading  hyphae 
iv^ue  aInio>t  >iniullaiieously  with  new  nnitlets  whieh  an*  pnMlui*«t|  bv 
the  pl.mt  in  i\^  elTort  to  ree«*tab!i>^h  its  resources.  This  pnNH^s  got-^  i»n 
fc!r:idually  and  >lowly  or  more  ra))idly  de|x*nding  naturally  \i\Mm  the  vigor 
of  the  plant.  I'iiially  the  |NT*«i>tent  efforts  of  the  fungtis  n*sult  in  deen-ik'^ 
uig  Mf-NN.  Ml  ftii'^tratinL;  the  growth  of  the  t ulnars.  lN>cau.s<*  of  lack  of  Um^i 
su|>phe'^  from  the  roots.  :nu\  eventually  in  the  production  of  m*rial  tuliers. 
.Meanulule  harve>t-time  ha>  arrive<l,  what  tuln-rs  an»  there,  are  har\*este«l. 


1917]  G^ssow:  Rhizoctonia  on  Potato  213 

but  the  roots  infected  with  sclerotia  remain  in  the  ground,  since  they  are 
not  pulled  up  by  the  digger  or  are  at  any  rate  returned  to  the  ground.  With 
the  diminishing  food  supply  in  these  roots,  sclerotia  develop  ready  for 
subsequent  attacks.  This  observation  also  accounts  largely  for  the  soil 
contamination  and  the  persistence  of  the  organism  iQ  land  once  infected. 
It  also  indirectly  suggests  a  new  means  of  control,  viz.,  the  prevention  of 
infection  by  cultural  methods  or  the  appUcation  of  fertilizers  producing 
vigorous  plants  in  the  first  instance  and  aiding  in  the  production  of  a 
generous  supply  of  new  feeding  roots. 
Central  Experimental  Farms 
Ottawa,  Canada 


SYNTHETIC'  C  ULTURE  MEDIA  FOR   WOOD-DESTROYINT. 

FUNC.r 

Ernbst  J.   PiEPER,   C.   J.   Humphrey   and  S.   F.   Acrbb 

Wood-destroying  funfd  grow  readily  on  many  of  the  ordinarj'  culture 
media  which  have  as  their  principal  ingredients  malt  extract  or  plant 
decoctions  and  meat  extracts,  usually  hardened  with  agar-agar  or  gelatin. 
As  an  example  of  such  media,  a  malt  extract  preparation  of  the  following 
formula  has  proved  very  satisfactory  for  gt»neral  culture  work: 

Extract  of  1  pound  lean  }k>cP  in  distilled  water 1000  cc. 

Malt  extract 25  grmmfl 

Agar-agar 20  grama 

This  hiis  found  a  wide  us*»  in  Europe  and  luis  \)een  emplo^Td  for  much 
of  the  routine  work  in  the  piithological  section  of  the  Forest  PhmIucUi 
I>iilK>rator>'.  In  certain  lines  of  investigation,  however,  such  as  the  test- 
ing of  the  toxicity  of  chemical  sul)st.iinc<»s,  and  in  compiirative  Xe»Xs  on 
the  physiological  U'havior  of  w(M>d-<Ic^troying  fungi,  this  medium  ht^ 
the  s<Tious  disa<  I  vantage's  of  lx*ing  chemically  complex  and  variable. 
Its  composition  and  constitution  <lepend  upon  the  nature  of  the  meat 
and  malt  extract,  the  method  of  preparation  and  the  duration  of  stan<iing. 
and  physically  it  may  1k»  variably  <'oIloidal.  Tlie  |M)ssibility  of  chemi- 
cal or  physical  combination  of  c<»rtain  pr(»serv'atives  with  the  highly  com- 
plex organic  cotn|M>unds  and  also  the  coagidation  of  the  latter  by  elec- 
trolytes an*  of  cxtn»me  importance  also  in  toxicity  work. 

In  the  pn*s(*nt  work  an  attempt  was  made  to  prt^pan^^  a  synthetic  mcHiium 
which  wouhl  support  a  growth  of  wcMxUiestroying  fungi  at  least  as  gurwl 
as  that  on  the  malt  extmct  agar,  and  which  at  the  same  time  would  lie 
cf>miM>se<l  of  as  simple  constituent'^  as  |K»ssiblc.  The  medium  could 
then  U»  <iuplicat<Ml  at  any  time,  by  any  inv<»stigator.  pn)viile<l  the  ch<»mi- 
cals  UM»d  wen»  of  the  same  standani  of  purity. 

For  .satisfactory  growth  of  w(HM|-<l<»st roving  fungi  a  culture  miMiium 
mii*<t  have,  in  addition  to  certain  simple  inorganic  salts,  the  n€H*e9««ar>' 
coin|Mitind.^  to  furnish  lM)th  nitrogen  aiul  carlwin  in  a  f<*rm  n^dily  available 
to  the  fungii**.     .Vmmonium  stilts,  nitrates  and  a.^paragin  or  its  salts  have 


1 


Thf  pr«'M<rit  p:ip(*r  it*  otH>  of  four  pr('|):in*d  l>y  the  junior  authoc  (l*ieprr»  to 
parti:il  fultilhiH'tit  of  r«M|uirftiiriitM  for  th«'  d«'Kn'<*  of  I)<»('tor  of  I'hilofMiphy  in  thr 
liuvrrMty  tif  W  i.Hr«»njtin. 

'  l.:tt«'r  t«*f<t^  in  thiH  l:il)or:itory  indicati*  th:it    In'^f  in  (»f   littlr  or   no  advanta|[r. 
in  m:in>  c:im*m  it  luiiiirHhat  rcturdH  thf  growth  of  W(KNl-<i«*i4t roving  fungi. 


1917]    .     PiEPER,  Humphrey  and  Agree:  Synthetic  Media  216 

frequently  been  used  in  synthetic  media  as  a  source  of  nitrogen,  while 
various  carbohydrates  have  been  used  as  a  source  of  carbon. 

The  first  step  in  this  work  was  to  select  a  nutrient  solution  of  inorganic 
salts  with  di-ammonium  phosphate  as  the  source  of  nitrogen.  This  solu- 
tion was  used  as  the  basis  for  testing  the  nutrient  value  of  various  carbo- 
hydrates and  consisted  of  the  following: 

Di-potassium  phosphate  (KSHPO4) 4  grams 

Di-ammonium  phosphate  (  (NH4)2HP04).  • 2  grams 

Magnesium  sulphate  (MgS04.7H30) 2  grams 

Agar-agar  (powdered) 15  grams 

Distilled  water 1000  cc. 

Varying  concentrations  of  the  following  carbohydrates,  usually  20  or 
40  grains  in  a  liter  of  the  nutrient  solution,  were  used:  Lactose,  maltose, 
cane-sugar,  galactose,  glucose  and  glucosamin.  Growth  of  the  fungus*^ 
was  compared  with  that  on  malt  extract  agar  as  a  standard. 

The  organism  grew  fairly  well  in  every  case.  Cane-sugar  and  glucose, 
however,  gave  the  most  favorable  indications,  the  growth  on  the  cane- 
sugar  being  slightly  more  favorable.  Since,  however,  the  growth  might 
be  changed  by  using  other  nitrogen  sources  in  addition  to  di-ammonium 
phosphate,  it  was  decided  to  continue  the  use  of  both  sugars  in  further 
work. 

The  next  step  was  to  obtain  a  nitrogen  source  more  available  to  the 
fungus  than  di-ammonium  phosphate,  so  the  following  substances  were 
tested  by  adding  2  and  4  grams,  respectively,  to  a  liter  of  the  nutrient 
solution  containing  forty  grams  of  cane-sugar:  Asparagin,  sodium  aspara- 
ginate,  ammonium  asparaginate,  caffein,  guanidin  carbonate,  glycin, 
leucin,  creatinin  and  betain.  With  0.2  and  0.4  per  cent  of  caffein  and  guani- 
din carbonate,  respectively,  no  growth  of  the  fungus  occurred,  but  in  all 
the  other  cases  a  fairly  good  development  was  secured.  The  best  growth 
was,  without  doubt,  obtained  with  asparagin  and  its  sodium  and  ammoni- 
um salts.  The  fact  that  asparagin  alone  might  be  a  source  of  available 
carbon  for  fungi  was  considered,  but  experiments  showed  that  practically 
negative  results  were  obtained  in  the  absence  of  a  sugar. 

Glucose  was  next  substituted  for  cane-sugar  while  using  asparagin  and 
di-ammonium  phosphate  as  a  source  of  nitrogen.  The  character  and 
rate  of  growth  was  the  same  as  that  obtained  with  cane-sugar.  It  has 
been  shown*  that  not  all  fungi  contain  an  enzyme  which  will  hydrolyze 
cane-sugar,  hence  the  substitution  of  glucose  would  presumably  be  an 
advantage,  and  cane-sugar  was  therefore  discarded. 

*  Fames  annosus  was  used  in  all  the  preliminary  tests. 

*  Boeseken,  J.,  and  Waterman,  H.  Akad.  We  tense  h.  Amsterdam,  20:  548.  1911. 
Abstract  in  Bot.  Gaz.  69:  413.     1915. 


216  PinTOPATHOLOGY  (VoL.  7 

On  the  ha^is  of  th««o  cxix^rimcnta  a  culture  medium  of  the  following 
composition  was  selected  for  further  test: 


Ctlucose  (CJiijOi),  powdered 40.00 

Di-potassium  phoHphate  (KjHPOi) 4.00  Krams 

Ajtparagin  (C«Ht()|Xj) 4.00  gnuns 

Di -ammonium  phosphate  (  (NH4)iHP04) 2.00  grmim 

Mafcnesium  sulphate  (MgS04.7HsO) 2.00  Krams 

( *alcium  carlMmate  (('aCO|) 0. 25  {(rmm 

Calcium  chloride  (CaClj) 0. 10  gram 

Afcar-agar  (powdered) 15.00  grmms 

Distilled  water 1000.00  cc. 

It  is  evident  that  thb<  medium  Is  synthetic  except  for  the  agar-agar^ 
which  is  used  lis  a  sohdifyinfc  agent.  Its  nutritive  properties  for  four  im- 
portant wckmIh  lest  roving  fungi  wen*  determined.  As  a  comparison,  simi- 
lar t<*sts  were  made  on  another  medium  differing  only  in  the  8ul)«titution 
of  Witte's  |)eptone  for  jusparagin  and  di-ammonium  phosphate.  Although 
this  latter  medium  is  not  strictly  synthetic,  still  a  definite  grade  and  purity 
of  the  {)eptone  can  1k»  obtained  from  a  reliable  source.  For  many  pur- 
pos4's  such  a  medium  might  Im*  found  of  considerable  advantagt%  as  has 
Imhmi  shown  by  t<*sts  on  Fotnes  (trirwsn:<  and  Fomen  pinicola  rt»|X)rte<l  later. 

In  pn»paring  the  synthetic  me<lium,  the  mixtun*  was  heatcnl  in  a  1.^ 
liter  fljisk  in  a  watiT  bath  to  prevent  charring.  It  was  then  pounnl  into 
test-tulK»s  lis  quickly  as  iHJSsible,  and  well  stirred  during  the  operation 
to  avoid  losing  any  precipitate  that  was  formed.  The  tul)es  were  then 
pluggcMJ  with  cotton  and  sterilizcil  in  live  steam  (1(K)®(\)  without  pressure 
for  thirty  minutes  on  thrcH*  succi'ssive  <lays.  A  very  slight  pnn'ipitation 
was  f(nmd  in  the  lM)ttom  of  the  tulx^s  after  .*<terilizat ion.  This  was  pn>l>- 
ably  a  mixture  of  cal(*ium  and  magnesium  phosphat4*s  and  car)N>nat4^. 
\>  small  amounts  of  calcium  salts  s<H»m  to  incn»a.M»  the  vigor  of  the  gmwth, 
it  is  advi.sable  to  n^tain  this  s<Mliment  by  thoroughly  shaking  the  tulM^si 
U'ftjre  (xmring  into  jx^tri  disln^s. 

The  WitteV  |><>ptone  me<liuiii  wjis  pn»pan»d  in  the  .**ame  manner  :is  tlie 
synthetic*  and   wa>  <M»m|K)s<Ml  of  the  following  sul)stanc*f»s: 

(iliiroHi*  •( MiiiOci.  piiwdcrrd  40  (M)  fniinis 

I)i-pf>taHHiuiii  plio«4phati>  (KilllH),)  4  00  grama 

Witti-M  |M>ptoiii*  4  00  grams 

Mafcix'Miiiii  Hulph:it<>  MkS<  >4.7li;<  >)  2  00  grams 

< 'ulciufii  rarlHin:it(>    (':i( '( >] i  0  25  gram 

< ':ilriurii  rhl«»ritl«'     (*:i<'l:  0   10  gram 

VK^tr-aicnr    {Hiwdcrcd  ■  15  00  grams 

Dintitlrd  H.itor  1000  (K)  cc. 

'  ( 'iill<»i<ial  ;*ilirii*  :i*'n\  ha**  Imi'Ii  ummI  hy  Horiif*  wnrkrrs  ill  plai*e  uf  agar-agar  and 
might  U>  «if  advaritaKf  here  l»ut  the  writrrM  huvr  not  eX|M*rimented  with  it. 


1917]         PiEPER,  Humphrey  and  Agree:  Synthetic  Media  217 

The  malt  extract  medium  used  for  comparison  was  made  as  previously 
indicated.     It  was  tubed  and  sterilized  in  the  same  manner  as  the  others. 

All  these  media  were  tested  with  four  wood-destroying  fungi.  The 
tables  give  the  growth  of  these  at  25*^0.  over  varying  periods  up  to  twenty- 
eight  days. 

From  the  results  it  is  seen  that  the  synthetic  culture  medium  which 
produced  the  best  results  gives  a  good  growth  and  compares  favorably 
with  the  malt-extract  medium.  Perhaps  by  continued  cultivation  the 
fungi  may  gradually  become  adapted  to  the  new  medium,  giving  then 
better  results  than  were  obtained  in  this  investigation. 

The  Witters  peptone  medium  is  especially  good  for  the  growth  of  Forties 
pinicola  and  Fomes  annosus.  With  Lenzites  sepiaria,  and  especially  with 
Siereum  frustulosuniy  it  gave  less  favorable  results  than  the  other  two. 

By  additional  work  it  may  be  possible  to  improve  the  synthetic  medium 
further  so  that  it  will  give  a  better  and  more  uniform  growth  than  here 
described.  Such  a  medium  would  be  very  valuable  both  for  toxicity 
work  and  general  physiological  experimentation  with  wood-destroying 
fungi. 

In  addition  to  the  media  for  which  the  formulae  are  given  in  the  pres- 
ent paper  sixteen  other  preparations  were  tried.  The  proportions  given 
are  for  1000  cc.  distilled  water  and  1.5  per  cent  agar.  None  of  these  were 
as  satisfactory  as  those  reported  above. 

1.  Cane  sugar,  40  grams;  ammonium  asparaginate,  4  grams;  magne- 
sium sulfate,  2  grams. 

Gave  thick  but  slow  growth  for  Fomes  pinicola;  wMi  Fomes  annosus 
gave  thin  growth,  covering  the  plate  in  two  weeks. 

2.  Fraenkel  and  Voges'  Solution.^ 
Gave  verv  poor  growth. 

3.  Fermi's  Culture-Fluid. « 

Gave  poor  thin  growth;  plate  not  covered  in  three  weeks. 

4.  Uschinsky's  Solution.® 

Gave  poor  thin  growth;  plate  not  covered  in  thre(i  weeks. 

5.  Modified  Uschinsky's  Solution.* 
Gave  very  poor  growth. 

6.  Hasselbring's  Solution.^ 

7.  Cane  sugar,  40  grams;  glycerin,  40  grams;  asparagin,  4  grams;  mag- 
nesium sulfate,  2  grams;  di-potassium  phosphate,  4  grams;  di-ammonium 
phosphate,  4  grams. 

Gave  best  growth  for  Fomes  annosus;  thin  growth  for  Fomes  pinicola; 
thick  but  slow  growth  for  Fomes  applanatuSy  Lenzites  sepiaria  and  Siereum 
jrustulosum. 

*  See  E.  F.  Smith,  Bacteria  in  relation  to  plant  diseases,  Vol.  I,  p.  197,  1905. 
"*  Glucose,  1  gram;  ammonium  nitrate,  1  gram;  di-potassium  phosphate,  0.5  gram; 
magnesium  sulfate,  0.25  gram. 


218 


Phttopatholoot 


(Vol.  7 


TABLE  1 
Radial  growth  in  millimeUrs  of  Pome*  annas tu  in  pariouM  media  at  iS^C, 


MEDIUM 

NUMBBB  or 
rBTBt-DIUI 

BADIAL  OBOWTB  OT  rCMmVB  W 
MXLLMMWtmwm 

7d«JB 

lOd^ys 

M  dAf* 

Synthetic < 

Peptone .    < 

Malt-<»xtract | 

1 

r 

2 
2' 

3 
3' 

21-23 
23-24 

23-24 
24-26 

•24-25 
»V-28 

30-34 
31-35 

35^37 
33^39 

29-34 
30-35 

40-12* 
40-i8* 

43-44* 

40-42* 

40-43* 
41-45* 

Character  of  growth: 

Synthetic.  Slightly  more  fliifTy  and  slightly    leas   dense    than    on    mmlt- 

extract,  although  the  color  was  the  same. 
Peptone.  Alx)ut  the  same  as  on  synthetic  medium  but  not  quite  as  denat. 

Malt-extract.     Dense,  creamy,  fluffy  growth. 
The  growth  of  Fomen  annosus  on  synthetic  medium  and  peptone  medium  was 
tested  for  acidity  with  litmus  and  found  to  give  a  slight  acid  reaction  after  fourteen 
days  growth. 

•Surface  of  medium  entirely  covered. 

TABLK  3 
Radial  growlh  in  milUmrtrrs  of  Fomrn  pinirola  in  variotix  media  at  tS*C. 


MBOIL'M 


I 
pEmi-Diaa 


RADIAL  OHOWm   OT  Pt'NUt'S  IH   MnXIMBTBBS 

14  fUys         !        ?1  dar* 


limyn 


10  <Uy» 


Synthetic 


1 
1' 


24-28 
24-2t5 


2  21-22 


l*rpt«iiie 


•>' 


2<>-32 
27-a3 


33-35 
30-35 


Surface 
covered 

Surface 
ctivrred 


31-32       Surface 

covere<l    , 
Surface        ■ 
cnvennl 


31-32 


Mnlt-4»\tr:irt 


3 


JfV  27     !     32-:«     I  Surface 

coveriMl 
32-.'M     :  Surface 


2.7  27 


covered 


Character  of  growth: 

Synth*' tii'.  Thill  iirid  Htriatni.  rotor  i«:tme  as  on  malt -extract  medium 

iVptoiiv  Wry  fluffy  and  juMt  .hm  di*niH'  ns  on  malt -extract  medium 

.Mttlt-fxtrart.     White.  denHe.  fluffy  growth. 


1917]        PiEPER,  Humphrey  and  Agree:  Synthetic  Media 


219 


table  3 

Radial  ffrowth  in  millimetera  of  Lemites  sepiaria  in  variotts  media  at  $S^C. 


MKDXUIC 

NUM- 

BBBOF 

PBTBI- 

DI8B 

RADIAL  GROWTH  OF  FUNGXTS  IK  mU.imTBBS 

7  days 

10  days 

14  daya 

21  days 

28  daya 

* 

1 

21-22 

30-31 

33-37 

Surface 

Synthetic 

1' 

22-23 

'31-32 

37-38 

covered 
Surface 

k 

covered 

* 

2 

17-20 

2&-30 

34-35 

37-39 

Surface 

Peptone - 

2' 

16-20 

29-31 

35-36 

36-39 

covered 
Surface 

b 

covered 

* 

3 

17-18 

27-n30 

33-35 

Surface 

Malt-extract - 

3' 

17-20 

29-30 

36-38 

covered 
Surface 

k 

covered 

Character  of  growth: 

'  Synthetic.         Margin  of  growth  thin  with  much  sub-growth;  more  fluffy 

towards  center  than  on  malt-extract;  color  not  as  dark  as 
on  malt-extract  medium. 
Peptone.  Growth  poor  in  appearance;  color  same  as  on  malt-extract 

medium. 
Malt-extract.    Fairly  dense;  dirty  brown  color. 

table  4 
Radial  growth  in  millimeters  of  Stereum  frustidosum  in  various  media  cU  B5^C, 


MEDIUM 

NUM- 
BER OF 
PETRI- 

DISH 

RADIAL  GROWTH  Ol 

'  FUNGUS  IN  MILLIMETERS 

7  days 

10  days 

14  days 

21  days 

28  days 

» 

1 

9-12 

14r-16 

29-33 

Surface 

Sjmthetic • 

V 

10-11 

15-19 

28-34 

covered 
Surface 

k 

covered 

Peptone < 

2 

4r-5 

5-6 

&-9 

9-10 

10-11 

2' 

7-« 

9-11 

10-13 

12-13 

13-14 

» 

3 

11-16 

21-22 

26-28 

30-36 

Surface 

Malt-extract i 

3' 

13-14 

22-23 

27-29 

36-37 

covered 
Surface 

k 

• 

covered 

Character  of  growth: 

Synthetic.  Very  fluffy,  dense  and  creamy;  slightly  more  brown  in  color 

than  on  malt-extract  medium. 
Peptone.  Poor  growth;  deep  orange-brown  color. 

Malt-extract.    Fluffy  growth;  slight  yellow  tint. 


220  Phytopathology  |Vol.  7 

8.  DifTrrs  from  No.  7  in  substitution  of  40  gmnis  Kalactogo  for  th«* 
vnm*  suj[;ar. 

(lavi*  inurh  slowcT  growth  than  No.  7;  platr  not  (\\uiv  covitcmI  in  thnt- 

WiM'ks. 

S),  Differs  from  No.  7  in  substitution  of  40  ^ranis  lactose  for  th«-  ran*- 
sUKur. 

( lavr  slow  growth,  not  as  rocmI  as  No.  8;  platr  not  cov(T<hI  in  thn***  \v«i*kv 

10.  Canr  sug:ir,  40  ^^rains;  glycin,  4  ^ranis.;  (li-])otassiuni  phosphate. 
4  j^rams;  nia^n<^iuni  sulfati',  2  Rraujs. 

(lave  frmyi]  jjjrowth;  almost  as  rapid  as  on  nialtn'xtract  agar,  but  ap|x-ar- 
anr<'  not  as  j^ood  as  on  No.  1. 

11.  DifTrrs  from  No.  10  in  substitution  of  4  grams  rrratinin  for  th«- 
glyrin. 

(•a VI'  fair  growth:  platr  covircd  in  thriM*  wrcks. 

12.  DitTiTs  from  No.  10  in  thf  sul)stitution  of  4  grams,  caflfrin  for  th«- 
glyrin. 

No  growth  in  thn-t*  wrrks. 

Mi.  l)iffrr>  from  No.  10  in  th«'  Mib«^tit\ition  of  4  grams  guani<lin  rar- 
l>onatr  for  thr  glyciii. 

(lavr  no  growth  in  three  weeks. 

14.  Cant'  sugar.  20  grams;  glucosamin,  4  grams;  (li-]><»tassiuni  phi**- 
phate.  4  grams;  magn«  vjum  sulfate.  2  grams. 

Fairly  good  growth,  but  less  deii^r  than  nn  maItHxtra<'t  agar;  plate 
<M)vere<l  in  two  wim  k*^. 

lo.  (Ilueosr,  2.")  grams;  d  and  l-leuein,  4gram>;  tli-|M»tassium  phos]>hat«*, 
4  grams;  magnesiinn  sulfate.  2  grams. 

Platr  eovrn-d  in  twn  wrrks  but  growth  thiiuur  than  on  No.  10. 

Hi.  Laeto>e.  'A2  gran'>;  brtain.  4  grams  ;di-iM)tassium  phosphatr.  I  Kni!ii«»; 
inagin  simn  sulfate.  2  grams. 

(Irowth  fair;  plate  not  cpiite  eovered  in  thn^e  weeks. 

LirKKATlKK 

.\s  praeti<-;dl\  all  of  th<'  literature  dealing  with  synthetie  eultun*  ni(Nii:i. 
a>  far  a>  tlu*  wrifi'r-  have  invest igati'd,  ha^^  n^ferenee  to  its  ada|)tabilit\ 
to  tlu'  growth  of  baet«Tia  or  mohls  and  as  thex'  organisms  ap|):in*ntl\ 
H'aet  to  the  media  in  a  diffennt  manner  than  the  wtMKl-4h»>t roving  llyni**- 
nomyi-etes  ufN>n  which  thi'^  stu<ly  was  eondu<*ted  no  l»ibliograp)i\  i^* 
ap|M'ndtMl. 

I\\  K>in;\iin\>  IN  rouKsi  l*ArnnLn(;v.  HiHKAr  OK  Plant  Inoimhy 
In  (  uui'KHMioN  Wirn  thk  ToiiKsr  Piionrrrs  Labokatoky. 
Maoismn.  \Vim  onsin 


PHYTOPATHOLOGICAL  NOTES 

Apple  scab  on  the  twigs.  Does  the  apple  scab  {Venturia  pomi  (Fr.) 
Wint.)  pass  the  winter  on  the  twigs,  which  thus  become  a  source  of  in- 
fection? This  is  a  question  frequently  presented  to  the  American  plant 
pathologists.  The  presence  of  the  organism  in  the  twigs  has  been  re- 
ported by  a  number  of  workers,  but  the  first  satisfactory^  data  bearing 
on  the 'probabilities  of  this  being  a  source  of  infection  wei-e  presented  by 
Morse  and  Darrow  in  1913.^  They  gav(?  a  very  satisfactory  review  of 
the  literature  of  the  subject,  which  will  therefore  be  omitted  in  this 
discussion. 

In  the  latter  part  of  April,  1916,  the  attention  of  the  writers  was  called 
to  a  nimiber  of  diseased  apple  twigs  from  Freehold,  Monmouth  County, 
New  Jersey.  A  careful  examination  showed  that  the  organism  was 
Venturia  poniiy  and  that  the  conidia  which  were  present  in  great  numbers 
were  viable. 

The  twigs  showed  an  abundance  of  infection  for  several  inches  and  the 
bark  was  split,  thus  giving  them  a  very  ragged  appearance.  Directly, 
beneath  the  ruptured  bark  were  dense  masses  of  stromatic  growth,  which 
protruded  through  the  openings  and  produced  an  abundance  of  conidio- 
spores,  which  were  short  and  irregular  and  rested  on  still  shorter,  in  fact 
almost  equilateral,  irregular  basal  cells.  The  spores  were  typical  and 
agreed  in  shape  and  size  with  those  obtained  from  other  sources,  and 
grew  readily  in  culture.  We  are  unable  to  say  whether  these  spores  were 
formed  in  the  fall  of  1915  or  the  spring  of  1916,  but  it  is  very  evident 
that  the  organism  survived  the  winter  in  the  twigs. 

The  writers  did  not  have  an  opi)ortunity  to  examine  the  trees,  but 
Mr.  W.  B.  Duryee,  Jr.,  the  County  Farm  Demonstrator  who  sent  the 
twigs  to  the  Station,  reported  the  disease  in  abundance.  The  twigs  sub- 
mitted to  us  carried  an  abundance  of  the  organism,  and  the  infection 
extended  from  the  tip  back  some  12  to  15  inches,  but  was  most  severe 
near  the  tip. 

Many  of  our  New  Jersey  apple  growers  cultivate  their  orchards  so 

*  Morse,  W.  J.  Spraying  experiments  and  studies  on  certain  apple  diseases  in 
1913.    Maine  Agr.  Exp.  Sta.  Bui.  223.     1914. 

Morse,  W.  J.  Spraying  experiments  and  apple  diseases.  Maine  Agr.  Exp.  Sta. 
Bui.  252.     1916. 

Morse,  W.  J.  and  Darrow,  W.  H.  Is  apple  scab  on  young  shoots  a  source  of  spring 
infection?    Phytopath.  3:  266-269.     1913. 


222  PnYTOPATiioLoaY  [Vol,  7 

thoroughly  that  fallen  leaves  an»  vm'  scarce*  in  the  spring  of  the  y«-ar. 
However,  thc^>  same  orchards  will  some  times  pro<luce  an  abundance 
of  «lis4»ase<l  fruit.  Although  we  fully  realize*  that  a  s<»vere  inffTtion  may 
rt»sult  from  a  small  source,  we  have  for  some  time  lK»en  inclimHl  to  Ix^lieve 
that  there  must  Ik»  some  source  of  infection  other  than  the  asco>|M>n'!» 
foniUMl  on  the  leaves  of  the  prec<*iling  year. 

Mkl.  T.  Cook  aSd  C\  A.  Schwarze 

On  Uiciug  an  ether  freezing  microtome  in  warm  atui  damp  ire/ither.  MoMt 
|M*rsoiis  who  use  an  ether  fn^'zing  microtome  may  rememU*r  that  during 
the  warm  and  humid  davs  of  midsummer  and  earlv  fall  then*  is  likelv  to 
Ik*  coiisitlt*ral)lc  ditiiculty  in  freezing  material,  wlu*n  at  otlitT  tinle^  littlf 
or  no  difficulty  i>  cx|M*rienc(>d.  During  the  very  damp  and  rainy  day^ 
of  f»arly  sumnuT  (P.)H»)  much  difficulty  of  this  sort  was  ex|N*rienc<Ml  in 
the  I^il>orat(»ry  of  Fon'st  Pathology,  Providence,  K.  I.  At  times  it  was 
absolutely  imiM>ssible  to  frcM^ze  the  pn*paration.  This  IcmI  to  sonn*  «*x- 
IM*rimenting  on  the  part  of  Mr.  N.  <).  Howard.  CollalKirator.  ami  the 
writer,  whit-h  liniilly  n'sulted  in  oven*<»ming  tin*  main  difficulty  in  a  vcr>* 
simple  and  effi<*ient  maimer.  The  a|>paratus  <*:)nsisted  m<*n*ly  of  a  widt^ 
mouthe<l.  eight-  or  ten-ounce  l>ottle  containing  anhydr(»us  calcium  chloride. 

which  was  in.^MTted  )N'twe(*n  the  pn'ssure  tatik  and  tlu*  atomizer.     Thbi 

• 

lM>ttlt*  was  connect<Ml  so  that  tlu*  air  from  tlu*  tank  pri-vsed  thn»ugh  a  glasei 
IuIn*  in  the  stop|M*r  to  the  hott  >m  of  the  botth*.  and  tliencM*  up  thn>ugh 
the  mass  of  cah'ium  chloride  to  another  gla.ss  tiilH*  whi(*li  conncct4Hl  with 
the  atomizer  bv  means  of  a  rubiNT  tuU*. 

The  calcium  <*lil(»ri<le  w:is  broken  into  small  piec(\s  and  |»acked  intii 
the  Uittle.  but  not  .so  tightly  :is  to  pn*vent  the  long  glass  inlet  tuU*  U-inie 
worke<l  down  through  tlu*  mass  as  the  stop|)er  w:is  ins<*rt4*d.  The  nil»- 
Iht  stopiMT  was  tied  .s<»cun*ly  in  place  so  as  to  pn*vent  its  lM»ing  blown 
out   by  an  i'Xc«*s.h  of  air  pressure. 

.-\fter  a  few  (Livs  of  oc<*:i>i(»nal  u.s4*  the  calcium  chloride  usuallv  ^h4»u<*«i 
sign>  of  (leliqueMvme  through  absoiption  of  moi.stun*  from  the  air.  Wlten 
thi.s  deli(|uesn'nce  lN*came  rather  pn»nounc4*d,  tli<*  <'alciinn  cliloride  %ia> 
planMJ  in  a  small  "fry-pan"  and  heated  until  it  wits  again  entirely  dry  .tnti 
hard,  .\fter  it  had  c<K>h*<l  sufficiently  to  handle  it  was  bn»k(*n  up  into 
small  pi(M*(*s  and  put  back  in  the  Inittle  whih*  still  warm.  Tlie  same 
cah'ium  ehloride.  which  cost  l»ut  a  few  <*ents  when  |Mirchas(H|.  |i:ls  non 
N-eii  in  Use  for  nion*  than  six  months.  When  the  fnn*zing  microtome 
\\a.s  Us4*i|  M'veral  time>  each  day  the  <'alcium  chloride  hail  t4>  Ih'  t|rit*ii 
al'out  every  wi*ek  or  t**n  davs. 

.\lt hough  the  apparatus  df*MTilNMl   may  Ih*  consiflert*<l  lis  a   soniewh:it 
erude  affair,  it  has  worktMl  verv  effiri(*ntlv  for  mon*  than  six  m«inths  and 


1917]  Phytopathological  Notes  223 

has  given  no  indication  that  its  efficiency  would  not  continue  indefinitely. 
Without  doubt  a  more  finished  apparatus  of  still  greater  efficiency  would 
result  from  using  a  regulation  chemical  dehydrating  apparatus. 

Although  this  method  of  manipulation  usually  prevents  the  formation 
of  snow  on  the  imder  side  of  the  freezing  disk — ^which  delays  freezing — 
it  does  not  always  prevent  it.  Recent  experiments  by  Mr.  Howard 
show  that  this  difficulty  can  be  prevented  entirely  by  placing  several 
small  lumps  of  anhydrous  calcium  chloride  in  the  ether  bottle,  or,  better, 
in  the  ether  can  itself  as  soon  as  it  is  opened,  and  letting  it  stand  for  half 
a  day  or  a  day  before  using.  This  withdraws  the  small  amount  of  water 
in  the  ether,  which  apparently  is  partly  responsible  for  the  formation  of 
the  snow. 

In  using  ether  for  freezing  sections  we  have  always  found  it  necessary 
to  filter  the  ether  before  it  reaches  the  atomizer  and  also  to  avoid  using 
rubber  in  contact  with  it.  The  ether  intake  tube  in  oiu*  microtome  has 
an  inside  diameter  of  less  than  2  mm.,  and  filtering  is  very  easily  accom- 
plished by  thrusting  a  small  wad  of  cotton  into  the  end  of  the  tube.  This 
wad  of  cotton  also  is  extremely  useful  in  regulating  the  supply  of  ether 
going  to  the  atomizer,  as,  with  a  Uttle  experience,  the  supply  can  be  in- 
creased or  decreased  almost  at  will  by  using  respectively  a  loose  wad  of 
cotton  or  a  compact  one.  Of  course  the  cotton  used  for  filtering  should 
be  renewed  whenever  it  shows  any  tendency  to  become  clogged. 

This  note  is  offered  for  pubUcation  with  the  thought  that  other  workers 
who  have  had  similar  difficulties  in  freezing  material  with  ether  might 
like  to  know  that  such  difficulties  can  be  overcome  so  easily. 

J.  Franklin  Collins 

Note  on  Xyhria  polymorpha  and  X.  digitata.  The  recent  article  by 
Fromme  and  Thomas^  on  a  root-rot  disease  of  the  apple  in  Virginia,  in 
which  the  causal  organism  is  provisionally  referred  to  some  species  of 
Xylaria,  may  be  further  substantiated  by  the  following  observations. 

In  1906,  near  Scottsburg,  Indiana,  the  writer  collected  mature  speci- 
mens of  Xylaria  polymorpha  from  diseased  areas  in  living  roots  of  a  four- 
years-old  apple  tree  of  the  variety  Winesap.  The  following  year  this 
tree  died  and  was  pulled  up.  The  conidial  stage  of  the  fimgus  was  after- 
wards noted  on  the  diseased  roots.  On  October  5,  1908,  in  the  same  or- 
chard Xylaria  digitata  was  collected  from  the  roots  of  a  six-years-old  pear 
tree  which  had  died  from  some  unknown  cause.  In  the  writer's  herbarium 
are  two  other  collections  of  Xylaria  digitata,  made  at  Priest  River,  Idaho, 
from  decayed  areas  in  living  roots  of  Populus  trichocarpa  and  Crataegus 

1  Science  n.  s.  46:  93.     1917. 


224  Phytopathology  (Vol,  7 

douglam.  The  roots  of  the  former  wen*  partially  deca^'ed,  but  not  in 
the  same  part,  by  Fomea  applanatuSf  ami  those  of  the  latter  by  a  species 
of  Follies*  ix*culiar  to  this  trcK*. 

Jamek  K.  Weir 

Puccinia  triticina  Erikss,  Leaf -rust  of  winter  wheat  causes  damage  in 
Kansas,  It  is  j^encTally  e<)nsi<lenMl  that  the  leaf-nist  of  wheat  due  to 
Puccinia  triticina  Krikss.  is  not  s<»rious  enoiigh  to  cause  any  appreciable 
damaf^e  to  the  erop,  at  h>ast  publieations  indicate  that  an  attack  of  leaf- 
rust  in  May  or  June  does  not  produce*  any  marked  effect  on  the  yield. 

()l>w*r\'ations  by  the  \\Titer  th<'  past  season  showcnl  that  the  Ieaf-ni5t 
in  some  fields  in  Kansas  was  verv  abimdant,  an<l  that  its  occurrence  wa.* 
not  confim^l  to  the  folia^ce  but  that  the  "necks"  of  the  wheat  wen»  xngor- 
ouslv  attacke<l  bv  this  rust.  Careful  o!)serv'ations  and  examinatioa««  of 
«mch  fields  showed  that  no  othir  factors  could  have  lM»en  res|)oaHible  for 
the  p<H)r  cjuality  of  the  ^rain  and  the  rc<luced  yield.  The  yield  of  one 
variety  in  partic\ilar,  a  pure  line  winter  wheat  ^own  in  Kansas  and 
called  P  7(M),  was  re<hic<Ml  8K  jxr  cait,  acconlinR  to  yiehl  data  fumishe<l 
by  th<»  Deimrtnii  nt  of  AKnnnnny.  The  fields  showing  the  effect  nwirt 
were  thosi'  whi<-h  had  bi'^'n  planted  lat<*.  It  is  thought  that  this  is  par- 
tially resjxmsible  for  the  lar^c  percent ag*'  of  leaf-rust. 

The  iMTcentaKe  of  infection  on  the  "necks"  of  the  wheat,  as  e;^iniat<*d 

•by  the  newly  adoi)ted  scale  for  estimating  nist  iMTcentafC^^s  of  the  Officf 

of  Cereal  Investigations,   I)e|mrtment  of  ARriculture,  was  10  to  25  per 

cent,  while  the  folia^*  of  thf  alM»ve-mentionc»<l  variety  Renendly  showwl 

KM)  JXT  cent  of  infection. 

It  is  iM'lievi'd  bv  the  writer  that  the  leaf-nist  of  winter  wheat  in  Kansas 
can  under  favorable  conditions  ca\Ls<*  con.sidenible  damage  and  that  t<Mi 
little  stress  has  In^en  Riven  in  literature  to  the  imi>ortance  of  this  rust. 

L.  K.  Mku*hers 

Earhj  (liacwery  of  white  ptne  blister  rust  in  the  Vnitni  States,  Then* 
has  nHM*ntly  come  to  the  atU'ntion  of  the  writer  the  fact  that  a  siM»cinien 
<if  white  pin«*  blister  ru>t  was  c(»llceted  nii  white  pine  iPinus  strobus  Linn,  i 
by  Mr.  Samui'lN.  Haxt«T  of  Philadelphia,  in  April,  HM^o.  at  a  nurs«*r>'  n^-ar 
Philadflphia.  A  s«-arch  of  the  (>orresi)ondence  in  thr  files  of  the  rnited 
Stat«-*«  I>4*partmrnt  of  AKri<'ultiin*  cnrrolnirates  this  statement. 

The  »»p<rinMn  whi<'h  wa>  sent  t4i  the  TnitiHl  States  |)<*|mrtm«*nt  of 
AKrirultun-  w;i>  r»'f«TnM|   to  th**   Mycoloj^ist,   Mrs.   F.   W.  Patters<in.  f«»r 

I  \\v\f.  J:iiii«-  \{  Nfiti'H  nti  \%M<HlHli>itrii>iiiK  fiiiifei  which  ftrow  on  Uith  romfrmui 
and  'Iff  nlii'Mi-  xrw^    I.     Phyi<i|):itli.  4:  J72.     VA\. 


1917]  Phytopatuological  Notes  225 

examination,  and  pronounced  "a  Peridermium  which  causes  what  is  called 
a  pine-blister  rust." 

A  search  in  February,  1917,  in  the  pathological  collections  of  the  Bureau 
of  Plant  Industry  failed  to  reveal  the  specimen.  The  letter  from  Dr.  L.  O. 
Howard,  dated  April  22,  1905,  referring  the  specimen  to  Dr.  A.  F.  Woods, 
has  the  notation  on  it,  *  White  Pine,  Peridermium  on'*  in  the  handwriting 
of  the  Mycologist. 

Since  there  is  no  reason  to  believe  that  the  determination  was  incor- 
rect, and  since  but  a  single  species  of  Peridermium  has  ever  been  reported 
as  causing  a  blister  rust  on  white  pine,  this  specimen  was  in  all  probablity 
Peridermium  strobi  Klebahn,  the  pine  stage  of  Cronartium  rihicola  Fisher. 
This  record,  then,  antedates  the  finding  by  Stewart  of  the  Cronartiiun 
stage  on  currants  at  Geneva,  New  York,  in  1906,  and  the  hitherto  earliest 
record  in  this  country  of  the  Peridermium  stage  on  pine  discovered  in 
New  York  on  June  8,  1909,  and  reported  by  Spaulding  in  1909. 

Roy  G.  Pierce 

Needle  rust  on  Pinus  resinosa.  In  June,  1916,  the  writer  saw  at  Sharon 
Vermont,  a  very  striking  case  of  needle  rust  in  a  plantation  of  10,000 
trees  of  Pinus  resinosa  about  4|  feet  in  height.  Up  to  about  3  feet  the 
yellow  spore  bodies,  although  small,  were  so  abimdant  on  the  1915  needles 
as  to  be  readily  discernible  15  to  20  feet  away,  single  needles  bearing  as 
many  as  20  pustules.  Hedgcock  has  identified  the  rust  as  belonging 
to  the  two  species,  Coleosporium  solidaginis  (Schw.)  Thimi.  and  C.  deHca- 
tulum  (Long)  Hedge.  &  Long.  The  alternate  hosts  were  abundant  in 
the  plantation  as  well  as  beyond  it.  This  seems  to  be  a  case  of  healthy 
trees  being  brought  to  that  locality  and  infected  by  the  fitngi  which  were 
already  present  on  the  herbaceous  hosts.  Because  of  the  abundance 
of  the  rust  the  writer  thought  it  might  be  a  serious  matter  to  such  small 
trees.  A  second  visit  made  in  September,  however,  showed  that  the 
needles  were  a  healthy  green  color  except  for  small  dead  spots  where  the 
rust  pustules  were  produced.  It  is  possible  that  the  damage  may  later 
become  more  evident  and  this  point  will  be  determined. 

Perley  Spaulding 

Notes  on  the  distrihution  of  the  bacterial  disease  of  western  wheairgrass} 
Until  recently  the  writer  had  not  observed  the  bacterial  disease  of  western 

*  O'Gara,  P.  J.  A  paper  read  before  the  meeting  of  the  American  Phytopathologi- 
cal  Society,  Columbus,  Ohio,  December  28,  1915. 

Abstract  published  in  Phytopathology  6:  98-99.     1916. 
Science  n.  s.  42:  616-617.     1915. 
Phytopath.  6:341-349.     1916. 


336  Phitopathology  [Vol.  7 

wheat-grass,  Agropyrmi  smithii  Rydlt.,  causoil  by  Aplatwbacter  Agropt/ri 
O'Oara,  4iut!<kic  of  two  cMunties  within  the  atato  of  Utah.  The  disease 
has  been  recently  found,  however,  occurring  on  wetrtem  wheat-grass  in 
throe  widely  wparated  districts  of  Montana,  namely,  Lewis  and  (,'lark, 
Broadwater,  and  IXht  Loilge  counties. 

Ab  noted  in  previous  papers,  this  disease  is  most  characteristic  in  that 
the  yellow  bacterial  oose  is  fuuml  to  cover  the  glumes  of  the  inflorescence 
and  appears  also  in  droplets  of  considerable  slie  on  the  outride  of  the 
^umes  and  un  the  sheaths.  It  also  causes  Minu>  dwar6ng  of  the  plants 
aa  well  aa  a  Ix'nding  of  the  stem  alwve  the  last  int^-mode.  When  the 
inflorescence  is  infected  gemiinable  see<ls  arc  not  produced. 

The  fact  that  this  disease  has  l>een  found  in  widely  separated  distrieta 
would  indicate  that  it  may  be  found  wherever  western  wheat-grass  grows. 
The  writer  would  appreciate  u  note  from  anyiine  finding  this  disea.'<e,  as 
he  is  interested  in  establishing  the  ext^'nt  of  is  distribution. 

P.  J.  O'Gara 

Thr  occurrence  of  Cotletotrichum  aolania^um  O'Gara  on  eggplant.  A  note 
cunreming  this  species  of  C'olletotrichum  was  publinhetl  as  an  almtrsct 
in  Phytopiithologj-.'     Later  ii  description  of   the  orgiminni  appeare<l  in 


Myi-<iloi;i:(  ■     At  tht-  time  of  pliblishiiiK  my  i-urliiT  nutts  there  was  M>me 
dimbl  a-  t.i  \h>-  |i:ir:i-iti-ni  of  thi-  m-w  -pc<'ii-s.     Ciiltun-s  wm-  exchangiil 

MiCiini    ('   .r      A  .li.»-:iM'  i.f  iln-  iiiKltricn  111  rill  hiiiiii-  nf  Irii-li  piitAUi  rnuard  by  ■ 
Ii<-»   ^|.ii...  ..t  l'Ml|.-i..lii,'|iillti        l'livrr>|):itli    4:    tl»   III        I'll). 

'•>(;, r,    ]•   .r      \.»  .fi,.,!...  .,rr..|l.ir..tri.l,i,..i:.[i.l  ni..r>in.  Myr..l.>Ki»  T:  :to -II. 


1917]  Phytopathological  Notes  227 

with  Dr.  J.  J.  Taubenhaus,  then  at  the  Delaware  Agriculture  College, 
who  concluded  that  the  organism  is  a  species  of  CoUetotrichum  and  that 
it  has  parasitic  tendencies  (oral  communication). 

During  the  summer  of  1916  the  writer  had  occasion  to  observe  a  field 
of  eggplants  in  which  fully  ninety  per  cent  of  the  plants  showed  wilt. 
At  first  it  was  supposed  that  the  wilt  was  due  to  a  Fusarium,  noting  only 
the  general  appearance  of  the  field.  A  careful  examination  of  the  plants, 
however,  indicated  that  Fusariiun  was  not  present  but  that  the  roots 
and  stems  were  badly  infected  with  the  above-named  organism.  Interior 
portions  of  infected  roots  and  stems  were  taken  under  sterile  conditions 
and  placed  in  culture  tubes,  where  the  organism  fruited  characteristically. 
No  other  organism  appeared  in  the  cultures  where  the  proper  precautions 
were  taken.     Even  in  mixed  cultures,  Fusariimi  did  not  appear. 

When  the  organism  was  studied  as  a  root  and  stem  parasite  of  the 
potato,  it  was  not  suspected  of  being  a  serious  wilt  fungus,  but  in  the  case 
of  the  eggplant  it  has  been  found  to  product  a  wilt  disease  similar  to  that 
•produced  by  Fusarium.  During  the  early  growth  of  the  plants  no  trouble 
was  noted,  but  about  the  time  some  of  the  earlier  fruits  began  to  mature, 
the  infected  plants  wilted.  This  condition  shortly  prevailed  throughout 
the  entire  field,  producing  an  almost  total  loss. 

The  field  in  which  these  eggplants  were  grown  had  supported  a  stand 
of  potatoes  the  previous  year  and  it  was  in  this  field  of  potatoes  that  the 
writer  first  found  the  above-named  organism.  From  specimens  collected 
in  this  field  the  original  description  was  made. 

This  note  is  published  in  order  to  give  notice  of  the  economic  character 
of  this  species  of  CoUetotrichum. 

'  P.  J.  O'Gara 

Personals.  Mr.  K.  E.  Quantz,  formerly  assistant  plant  pathologist  at 
the  Virginia  Experiment  Station,  has  become  plant  pathologist  to  the 
Brazilian  Government,  with  headquarters  at  Rio  de  Janeiro. 

Mr.  H.  E.  Thomas  has  resigned  his  position  as  instructor  in  plant 
pathology  at  the  Virginia  Polytechnic  Institute  to  accept  an  appointment 
as  assistant  pathologist  at  the  Federal  Experiment  Station  at  Mayaguez, 
Porto  Rico. 

Mr.  Fred  R.  Jones,  formerly  a  graduate  student  at  the  University  of 
Wisconsin,  has  been  appointed  to  the  position  of  pathologist  in  charge  of 
forage  crop  disease  investigations.  Bureau  of  Plant  Industry',  beginning 
April  14,  1917. 

Mr.  Gustav  A.  Meckstroth,  a  student  at  Pennsylvania  State  College, 
has  accepted  an  appointment  as  scientific  assistant  in  plant  pathologj', 
Office  of  Cotton,  Truck  and  Forage  Crop  Disease  Investigations,  Depart- 
ment of  Agriculture,  beginning  May  1,  1917. 


LITERATURE  ON  PLANT  DISEASES* 

Compiled  bt  Eunick  R.  Obbrlt,  Librarian,  Burbau  op  Plant  Industry,  amb 

Florkncb  p.  Smith,  Absibtant 

February  to  March,  1917 

Arthur,  Joseph  Charles.    Uredinales  of  Porto  Rico  bsBod  on  collections  by  H.  H. 

^lietiel  and  E.  W.  Olive.    Mycolofda  9:  55-104.     F.  1917. 
Bloletti,  Frederic  Theodore  and  Bonnet,  Leon.    Little-leaf  of  the  vine.    Jour.  Agr. 

Research  8:  381-398,  2  fig.,  pi.  89  02.     Mr.  6,  1917. 

"A  disease  of  the  vine,  vyinfc  in  seriousness  with  oidium  and  phylloxera." 

Cause  unknown. 
Blsby,  G.  R.    The  short -cycled  Uromyces  of  North  America.     (Abstraei.)  Phjrto- 

pathology  7:  74.     F.  1917. 
Blake,  Msurice  A.,  Cook,  MelvUle  Thurston,  and  Schwsrze,  Carl  Alois.    Studies  on 

peach  yellows  and  little  |>carh.     (Abstract.)     Phytopatholoay  T:  76-77.    F. 

1917. 
Block,  W.  S.,  and  Ruth,  W.  A.    Control  of  apple  scab  by  bleaching  powder.     (Ab> 

stract.)     Phytopathology  7:  76.     F.  1917. 
Brooks,  Charles,  and  Cooley,  Jscquelln  Smith.    Jonathan  spot.     (Abstract.)    Phy- 
topathology 7:  76.     F.  1917. 
Tom|)eraturc    relations   of   apple    rot   fungi.     (Abstract.)    Phjrto- 

pathology  7:  76.     F.  1917. 
Brown,  Nellie  Adaless.    A  bacterial  stem  and  leaf  disease  of  lettuce.     (Abstract.) 

Phytopathology  7:  63.     F.  1917. 
Boiler,  Arthur  Henry  Reglnsld.    Black  rust  of  wheat.     Bui.  Misc.  Inform.  Kew, 

1917:  4K.     F.  1917. 
I'>ononiir  1<his  due  to  m'hoat  rust  in  North  America. 
Bnrkholder,  W.  H.    Bean  diseases  in  New  York  8tate  in  1916.     (Abstract.)    Phyto* 

pathology  7:  61.     F.  1917. 
Dry  rcN>t  rot,  Futiarium  sp.;  blight,  BacUrium  Pfuueoli. 
Butler,  Ormond  Rourke.    How  to  control  the  snapdragon  rust. 

FhiriHts*   Kx.  4S:  353.     F.    17.    1917. 
Dusting  with  sulphur. 
Bysri,  Luther  Psrrls.    A  nomatrMle  diHcase  of  the  dasheen  and  its  control  by  hoi 

wat<*r  tn'tttmcnt.     (.Mwtrart.)     Phytopathology  7:  66.     F.  1917. 
Tylenchtui  triliri  on  whrat.     Phytopathology  7:  56-57.     F.  1917. 


'  fWfttnntnc  with  this  numbrr.  it  i*  intrndvtl  that  this  liat  thmll  includ*  all  r«f «f««MB l» Um 
luf«  ol  plant  lii  t'mar*.  bbtb  Amn-lrmn  and  f«»f«lgn      All  forriga  mrinekf  publiabad  MBO*  Jmumtt  I.  tflft 
•  hirh    itnif  t-.i  our  Bttrtiti'in.  «ill  hr  rntrrcii.  wi  that  th«  imirs  may  hm  ulttmAlvly 
from  tlut  (lat* 

Ail  aut>tor«  ar«>  "rfirl  Ut  loi'iprratr  in  makinc  thv  lt*t  C(im(»l«.#  by  ft«ndittc  Ibair 
ibC  r«>rrrviftn«  aiiit  aiMitmn*.  atwl  r«|imall>   by  rallinc  ait4*titi<>n  to  mrht4>n<iua 
nf  rvBular  |ii-irnaU       iip|irifit«  <»r  r<irTM*|M»fMlFtirfl*  •liuulil  tie  aililrrMd  lu  Miaa   K.    R 
BiirvAU  i4  IMabt  loduMo.  l*.  .*<   I>*p«    Agrx  ,  WMhit^ton.  I).  C. 


1917]  Literature  on  Plant  Diseases  229 

Carsner,  Eubanks.    Do  the  bacteria  of  angular  leaf  spot  of  cucumber  overwinter 

on  the  seed?     (Abstract.)    Phytopathology  7:  61-62.    F.  1917. 
Chivers,  Arthur  Houston.    The  injurious  effects  of  tarvia  fumes  on  vegetation. 
Phytopathology  7:  32-36.    F.  1917. 
Bibliographical  footnotes. 
CoUey,  Reginald  Hunter.    Discovery  of  internal  telia  produced  by  a  species  of  Cron- 
artium.    Jour.  Agr.  Research  8:  329-332,  pi.  88.    F.  26,  1917. 
Literature  cited,  p.  332. 
Cronartium  ribicola. 

Mycelium  of  the  white  pine  blister  rust.      (Abstract.)      Phytopathology 

7:  77.    F.  1917. 
Cronartium  ribicola. 
Pycnial  scars,  an  important  diagnostic  character  for  the  white  pine  blister 


rust.     (Abstract.)    Phytopathology  7:  77.    F.  1917. 
Cromwell,  Richard  O.    Fusarium-blight,  or  wilt  disease,  of  the  soybean.    Jour. 

Agr.  Research  8:  421-440,  1  fig.,  pi.  95.    Mr.  12,  1917. 
Literature  cited,  p.  438-439. 
Ftaarium  tracheiphilum  Smith. 
Cuba.    Secretaria  de  Agricultura,  Comerdo  y.Trabajo.    Comlsion  de  Sanidad 

Vegetal.    La  enfermedad  del  cocotero,  y  medios  para  su  exterminio.    Cuba 

Sec.  Agr.  Com.  y  Trab.  Com.  San.  Veg.  Circ.  2,  4  p.    S.  1916. 
La  enfermedad  del  platano  y  metodos  para  combatirla.    Cuba  Sec.  Agr. 

Com.  y  Trab.  Com.  San.  Veg.  Circ.  3,  4  p.    S.  1916. 
Dalbey,  Nora  £.    Com  disease  caused  by  Phyllachora  graminis.    Phytopathology 

7:  56-56,  1  fig.    F.  1917. 
Damell-Smlth,  G.  P.    A  disease  of  spring  flowering  bulbs.    Agr.  Gaz.  N.  S.  Wales 

88:  141-142.    F.  1917. 
Davis,  W.  H.,  and  Johnson,  Aaron  Guy.    The  aecial  stage  of  the  red  clover  rust. 

(Abstract.)    Phytopathology  7:  75.    F.  1917. 
Uromycea  fallens  (Desm.)  Kern. 
Doran,  William  L.    Controlling  snapdragon  rust.    Value  of  copper  and  sulphur. 

Florists'  Ex.  48:  501.    Mr.  8,  1917. 

"Bordeaux  has  no  effect  on  the  rust  of  snapdragons,  and  will  not  control  this 

disease." 
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Gardener,  Max  William.    Dissemination  of  the  organism  of  cucumber  anthracnoae. 
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Gilbert,  William  Williams.    Virulence  of  different  strains  of  Cladosporium  eum- 
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\  IVri<lermium  U'longing  to  Colecwporium  terebinthinace*.     (.\b- 

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1917]  Literature  on  Plant  Diseasi^  231 

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Johnson,  M.  O.  The  spraying  of  yellow  pineapple  plants  on  manganese  soils  with 
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Johnston,  John  Robert.  Enfermedad  de  la  rafz  de  la  cafia  de  azticar.  Pt.  II.  Ha- 
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None  of  the  main  fungi  concerned  in  rotting  either  the  oak  or  the  pine  slash 
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Lima  bean  mosaic.     (Abstract.)     Phytopathology  7:  60-61.     F.  1917. 

Peanut-wilt  caused  by  Sclerotium  rolfsii.    Jour.  Agr.  Research  8:  441-448, 

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McClliitock,  Jamei  A.  Will  SponKospora  subtcrranea  prove  serious  in  VirgiBiA* 
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forrfttH  f»f  the  nnrthMcHt.     ForcMtry  l^uart.  14,  no.  4:  567  577.     December.  1916. 
Wolf,  Frederick  Adolf.     .\  Miunnh  diHc:iM>  chummI  by  (*hoiinophora  cucurbit  a  rum. 

Jniir    Agr.   |{.  ^.•:l^h  8:  .'U**  :V2S.  pi    s.-^  s7.     F.  Jti.   1«»17. 


iPii^  nn*MH«»L'M.K  f«»r  .Vpril.  11M7  i7:  Vi   l.Vl.  PI.  II)  wan  iraucHi  Apnl  5. 
P.M7 


PHYTOPATHOLOGY 

VOLUME  VII  NUMBER  4 

AUGUST,  1917 

THE  CUPRAMMONIUM  WASHES 
Their  Preparation,   Biological  Properties,   and  Application 

O.    Butler 
With  Plates  III  to  X 

A  number  of  cuprammoniums  have  been  recommended  as  fungicides, 
but,  despite  the  fact  that  they  form,  or  it  would  be  more  accurate  to  say, 
could  be  made  to  form,  clear  solutions  and  leave,  on  drying,  inconspicu- 
ous spots  on  the  foliage,  no  single  one  has  sufficiently  met  the  desiderata 
of  practice  to  become  generally  employed.  Practice  demands  that  a 
fungicide  be  non-toxic  to  the  sprayed  plant  at  the  strength  at'  which  it  is 
most  efficient  and  effective,  but  the  cuprammoniums  have  the  reputa- 
tion of  being  unduly  toxic  and  of  not  being  as  effective  though  more 
efficient  than  Bordeaux  mixtures. 

The  toxicity  of  the  cuprammoniums  has  been  ascribed  to  soluble  cop- 
per (Millardet^  being  notably  a  proponent  of  this  view),  to  excess  am- 
monia, and  to  ammonium  sulphate.  The  prevailing  opinion  regarding 
the  ineffectiveness  of  the  cuprammoniums  is  based  on  their  behavior 
relatively  to  Bordeaux  mixtures  which,  in  fact,  is  comparing  solutions 
weak  in  copper  with  mixtures  considerably  stronger.  Hawkins,*  for 
instance,  compared  a  cuprammonium  containing  0.053  per  cent  copper 
with  Bordeaux  mixture  containing  0.18  to  0.25  per  cent  copper.  The 
question  may,  therefore,  be  asked,  are  any  or  is  any  one  of  the  cuprammon- 
iums worthy  of  being  retained  amongst  the  fungicides?  In  order  to  satis- 
factorily answer  this  question  it  will  be  necessary  to  study:  (1)  The  com- 
position and  preparation  of  the  different  washes.  (2)  The  relative 
toxicity  of  the  different  washes,  and  the  conditions  affecting  the  same. 

*  Millardet,  A.,  and  Gayon,  U.  Les  divers  proc6d68  de  traitement  du  mildiou 
par  les  composes  cuivreux.    Journ.  Art.  prat.  1:  729.     1887. 

•  Hawkins,  L.  A.  Grape -spraying  experiments  in  Michigan  in  1909.  U.  S. 
Dept.  Agr.  Circ.  65.     1909. 


236  -Phytopathology  [Vol.  7 

(3)  The  relative  efficiency   and   effectiveness   of  the  cuprammoDiumft. 
This  we  will  now  proceed  to  do. 

I.   CHEMISTRY    AND    METHODS    OF    PREPARATION    OF   THE    CUPRAMMON'U-MS 

In  the  preparation  of  the  cuprammonium  washes  met  with  in  practice 
either  animoniiim  hydroxid  or  ammonium  carbonate  are  employerl  an 
the  solvent,  the  solute  being,  in  the  case  of  the  former  solvent,  either 
copper  tuminf^s,  i.e.,  metallic  copper,  copper  sulphate^  the  basic  <*<»pper 
carlwnatc  malachite  (CuCOj.  Cu(()H)x),  or  the  basic  copper  carlK>DAt« 
of  Burgunily  mixture  (2  CuCX),.  3  ('u(()H),)»  and  in  the  case  of  the  latter 
the  copper  salts  mentioned,  together  with  basic  copper  sulphate  and  cu- 
pranunonium  sulphate  (CuS()4.  4  NHj.  HjO).  With  the  exception  of 
the  copper  sulphatisammonia  wash  which  Ls  a  cuprammonium  sulphate, 
all  the  other  waslu»s  preparwl  with  ammonium  hydroxid  produce  cupnuu- 
moniums  of  very  similar,  if  not  identic  composition  and  fonii  a  well 
charact<»riz(Hl  group;  similarly  the  wjisIh^  prepared  with  aimncmium 
carl)onato  an*  also  compositionally  so  ne^irly  alike  as  to  form  a  well  lie- 
fincnl  gn)up.  The*  fonner  ar(»  cuprammonium  hydrati^s,  the  latter  cupram- 
monium carlN)nat<^.  Since  (^uprammoiiium  sulphate  was  the  first  in- 
tnxluced  of  the  cuj)ramm<)nium  washes  and  the  cuprammonium  hydrates 
were  introduccHl  prior  to  the  cupranunonium  carlMmates,  it  will  lie  possible 
lK>th  to  n*tain  a  group  distribution  and  consider  the  M^veral  fungicid<<9(  in 
chn>nological  ord("ir. 

,4.  Cuprammonium  Kulphate  wafihen 

CopiHT  sulphnlv  and  ammonia.  The  copfx^r  sulphate  and  ainmunia 
wash  (ejiu  c^lc^stcO  was  the  first  iiitnKluc(Kl  of  the  cuprammonium  fungi- 
cidfw  and  still  n^nuiins.  taking  the  world  at  large,  the  l)ost  known.  It  15 
tlu*  most  easily  pn<^|)anxl  and  at  the  same  time  the  most  unstable,  even 
when  sufficient  amnumium  hydroxid  Ls  (iinployini  to  give  a  clear  h>Iii- 
tion.  The  fungicide  was  intHNluccnl  by  AudoynaucH  in  18S5,  but  the 
original  fonnula  which  is  as  follows: 


Cupriciiulphntr 1 

Aiiitiumiuiii  hydroxiti  ^p.  gr.  9()       0  769*  by  volume 

WiiXt'T  to  100 


*  li4Mifi)r(l.  Dukf  of.  uimI  Pick«*nnf(.  S.  l*.     Wotmrn  Kxperimental  Fruit  Fi 
H«pt    U:  S4i.     IIMO 

'  Aij«loyiiniiii.  A.     Ia*  miUlioti  c*t  Im  roinp<iA<'t<  cupriqucs.     Progrteagr.  el  nt. 

IKK'. 

*  Kfiuivnii-nt  of  animoniiim  hydrntr  up.  gr.  92,  1  part  by  volume  called  for  in  cht 
origpiml  foriiiula. 


1917] 


Butler:  The  Cuprammonium  Washes 


237 


proved  injurious  to  vegetation  and  has  suffered  ftiore  or  less  marked 
modifications  at  the  hands  of  subsequent  writers  as  will  be  seen  from  a 
perusal  of  table  1. 

TABLE  1 

Strength  oj  copper  sulphate  and  ammonia  wash  and  ratio  cupric  sulphate:  ammonium 

hydroxid  recommended  by  different  authors 


CUfRIC  SULPHATK 

STRBKOTH  IN  CUPRIC  SULPHATB 

AMMONIUM  HTDROZID 
SP.  OR.  0.90 

per  cent 

■ 

0.26 

1:1.50 

0.50 

1:0.76 

0.50 

1:1.06 

0.50 

1:1.70 

0.50 

1:1.14 

1.00 

1:0.73 

1.00 

1:1.06 

1.00 

1:1.46 

The  formulae  given  in  table  1  do  not  necessarily  represent  the  composi- 
tion of  the  fungicide  when  put  in  service,  however,  for  we  find  authors 
recommending  that  it  be  allowed  to  stand  after  being  made  for  a  few 
hours,  half  a  day  or  even  several  days*  so  that  the  excess  of  ammonium 
hydroxid  may  pass  off.  Nor  do  the  formulae  permit,  except  in  one  in- 
stance, i.e.,  in  the  case  of  the  wash  containing  1  per  cent  cupric  sulphate 
and  a  ratio  cupric  sulphate-ammonium  hydroxid  of  1: 1.46,  of  the  fung  - 
cide  being  applied  as  a  perfectly  clear  solution  which  is  essential  if  tlie 
copper  is  to  be  deposited  on  the  sprayed  foliage  in  the  proper  physical 
and  chemical  states.  Millardet^  long  ago  pointed  out  tliat  Audoynaud's 
formula  was  in  this  respect  defective  and  increased  the  amount  of  am- 
monium hydroxid  so  as  to  give  a  ratio  of  1:1.53  instead  of  1:0.769. 
The  ratio  cupric  sulphate  ammonimn  hydroxid  required  to  give  a  clear 
1  per  cent  solution  (and  Millardet's  figures  are  correct)  has  to  be  greatly 
increased  in  order  to  prevent  a  precipitate  forming  when  washes  contain- 
ing less  than  1  per  cent  cupric  sulphate  are  employed.  The  Duke  of 
Bedford  and  Pickering*  have  shown  that  the  amount  of  ammonium  hy- 
droxid required  increases  very  considerably  with  the  dilution  and  the 
data  presented  in  table  2  confirms  this  view.  But  while  the  data  given 
in  the  table  show  a  very  considerable  increase  in  the  amount  of  ammonium 

*  Viala,  P.    Les  maladies  de  la  vigne,  ed.  3,  p.  143.     1893. 

^  Millardet,  A.,  and  David,  E.  Essais  comparatifs  de  divers proc^ds  de  traite- 
ment  du  mildiou.  Compte-rendu  Congr^  nationale  viticole,  Bordeaux.  Appendix, 
60.     1886. 

•  Woburn  Exp.  Fruit  Farm  Rept.  11:  18.     1910. 


238 


Phytopathology 


(Vol.  7 


TABLE  2 
Amount  of  ammonium  hydrorid  required  }o  give  clear  nolutionM  of  copper  MtUpkmie 
and  ammonia  of  different  ntrengthn  in  cupric  sulphate  together  unth  the  corrt»pomd-' 
ing  ration  cupric  sulphate:  ammonium  hydroxide  and  percentages  of  ammonia 


VrRKNUTH    IN 


per  rtnl 

I  0 

0  '> 

0  2 

0  1 


AMOI'Nr   AMMONlim 

■TDSOXID   MBQt'lKBD  TO 

flIVB  rUBAR  ftOLUTIONi 


per  cent 

15 
1  0 
0  8 
0  7 


II4TIO 


CUPKIC  •rLTMATB 
AMMONII  M  HTDMOXIO 


1:15 
1:20 
1:4  0 
1:7  0 


IK  NHa  tn»m-Anri 

OMLT 


0  386 
0  2.SS 
0  251 
0  179 


'The*  data  given  under  the  heading  amount  of  ammonium  or  ammonium  rarliunjit^. 
as  thecaacmay  Iw,  required  to  give  a  clear  8olution  indicatea  the  amount  of  the  Milt 
required  to  give  a  clear  solution  for  a  ixTicMl  of  time  of  not  leiM  than  two  houm  in 
a  closed  veatM*!. 

hydroxid  n»lativo  to  tho  copper,  it  also  brings  out  equally  clearly  that 
the  al)solute  amount  of  anunonia*  in  solution  decreases  as  the  conr(*nt ra- 
tion of  the  copfMT  is  lowennl.  It  may  also  )>e  well  to  add  that  onitiK 
to  the  extn^mc;  volatility  of  ammcmium  hydroxid  the  fi^reit  given  in  the 
table  will  have  to  Ih»  inrnMistMl  at  temp<Tatures  much  alnive  20**(\  :uk1 
conversi»ly  may  1k»  somewhat  <h»rnjas(Ml  for  tomiKTatures  l)elow  2iY*i\ 

The  rop|NT  sulphate  and  ammonia  wash  may  l)e  most  conveniently 
prepare<l  by  adding  the  ammonium  hydn>xid  nH)uiro<l  to  a  strong  si>lu* 
tion  of  copfMT  sulphate  and  diluting  imnuHliately  after  the  pnH*ipitat« 
first  fonn<»tl  has  dissolvtui,  though  the  wash  may  Ih»  satisfactorily  pn»- 
pannl  even  when  the  n^lative  dilution  of  the  salts  varies  f^ithin  wxilc 
limits.  It  is  g(*4ierally  considi^n^l  that  the  copper  and  anunonia  wash 
(and  the  other  cupranunoniums)  are  In^st  pn^panni  with  soft  water  Mncp 
the  solutions  tin*.  d(H*ompos4Ml  by  hard  water.  The  amount  of  copper 
pnH'i(utate<i  wliftn  hani  water  b(  usimI  is,  however,  entirely  m^Ugible  in 
practi(*<»  lis  nuiy  Ih»  judgcMl  frofu  table  3.**       * 

TABI.K  3 
Am4>unt  of  cttpiHT  itrrripitated  from  thi  mpfur  »ulphnte  and  amm4ntia  womK  hy  ir«i.'rrt 

iff  difftrt  ut  dtgntM  of  htirdttrMx 


IM>I  tt'K   or  WATRR 


H%iibMiciM  or       I 

MrTHH-    OKllRKU    , 


corrva 
raBrirrr»Ti» 


(*ily  «if  liord«>.*iu\ 
(!nvoii  ykvW 


-.Yi  0 
92  0 


0  OOONt 

0  ocMm 


*The  ii'Tiu  afiiitionia  in  \imh\  to  denote  Nil,  unlefut  the  context  indicatm  tlie 
connotation  Ml  .Oil 

'*  Mdlardrt.  A  .  and  tiayon.  V.  Id**  divert*  prtWuirii  de  traitement  du  mtlcfaou 
par  Ira  comfHMM'i*  ruivreux.     Journ.  .\gr.  prat.  1:  7.Ti.     1KK7. 


1917]  Butler:  The  Cuprammonium  Washes  239 

When  ammonium  hydroxid  is  slowly  added  to  a  strong  solution  of 
cupric  sulphate  a  precipitate  of  basic  cupric  sulphate  (CUSO4.  2  Cu(OH)i) 
is  thrown  down  which  dissolves  in  an  excess  of  the  reagent  forming  a 
deep  blue  solution,  the  copper  being  then  in  the  form  CUSO4.  3  NHj.  2 
HjO"  or,  according  to  the  more  commonly  accepted  view  CUSO4.  4  NHs. 
H2O  a  salt  which  decomposes  readily  on  volatilization  of  ammonia  or  on 
dilution,  the  copper' being  precipitated  as  a  basic  sulphate.  When  the 
fungicide  dries  upon  foUage  the  copper  is  deposited  as  a  basic  sulphate 
mixed  with  a  Uttle  ammonium  sulphate  in  the  ratio  of  1:0.35;  in  other 
words  only  a  very  small  amount  of  the  latter  salt  can  be  present  even 
when  a  1  per  cent  solution  is  sprayed  on  foliage  as  will  be  clearly  seen 
from  a  study  of  the  reactions  involved  which  are  as  follows:" 

(1)  3  CUSO4  5  H2O  +  4  NH4  OH  =  CUSO4.  2  Cu(0H)2  +  2  (NH4)2S04 
+  15  HjO. 

(2)  CuSO..  2  Cu(OH),  +  2  (NHOjSO,  +  ;„  "' "T  =  3  (CuSO*.  4 

in  excess 

NHs.HjO)  +  9  HtO. 

(3)  3  (CUSO4.  4  NH3.H,0)  +  H2O  =  CUSO4.  2  Cu(0H)2  +  2  (NH4) 
SO4  +  8  NH, 

B,  Cuprammonium  hydrate  washes 

A  cuprammonimn  hydrate  is  formed  when  metallic  copper,  cupric 
oxide,  cupric  hydrate,  malachite,  or  the  basic  cupric  carbonate  of  Bur- 
gundy mixture  are  dissolved  in  ammonium  hydroxid,  and  washes  have 
been  used  in  practice  prepared  from  copper  and  all  the  copper  salts  men- 
tioned with  the  exceptions  of  cupric  oxid  and  hydrate.  All  the  cupram- 
monium hydroxid  washes  decompose  on  dilution  or  on  volatilization  of 
ammonia  with  formation  of  cupric  hydrate,  the  copper  also  being  de- 
posited in  this  form  when  the  fungicides  dry  spontaneously  on  foliage. 
The  cuprammonium  hydrate  washes  are  more  stable  than  cuprammonium 
sulphate. 

Copper  and  ammonia  wash.  The  copper  and  ammonia  wash,  or 
Schweizer's  reagent,  was  first  introduced  as  a  fungicide  by  Bellot  des 
Miniferes  in  1887"  but  despite  the  fact  that  the  results  he  obtained  are 
said  to  have  been  highly  satisfactory  it  is  practically  unknown  in  the 
literature. 

For  the  preparation  of  the  copper  and  ammonia  wash  a  very  large 
amount  of  ammonium  hydroxid  is  required  and  the  copper  must  be  acted 

"  Bedford,  Duke  of,  and  Pickering,  S.  U.  Woburn  Experimental  Fruit  Farm 
Kept.  11:  17.     1910. 

**  Chester,  F.  D.    The  copper  fungicides.    Journ.  Myc.  6:  23.     1891. 

"  Bellot  des  Mini^res,  H.  Ammoniure  de  cuivre  et  parasites  de  la  vigne.     1887. 


240  Phytopathology  (Vol.  7 

on  in  thc^  firesenco  of  air  or  traces  of  aniinoniuni  salti).  Bellot  de»  Mm- 
i^res  employed  the  fonner  method  and  prepared  a  stock  solution  whirh 
was  diluted  at  time  of  use  so  as  to  contain  0.25  to  0.75  per  cent  metallic 
copper,  i.e.,  the  copper  equivalent  of  a  1  to  3  per  cent  Bordeaux  mix- 
ture.    The  stock  solution  was  made  as  follows: 


Copper  turnings 1 

Ammonia,  up.  gr.  0.9 .' 119  by  volume 

A  stock  solution  prepare<l  in  the  manner  indicated  can  l)e  dilutc<l  with 
water  to  0.0^^17  per  cent  copper  without  a  precipitate  forming  within  a 
pericxl  of  two  hours.  At  this  dilution,  however,  the  solution  c<mt2iins 
0.97  pcT  cent  ammonia  which,  as  a  glance  at  table  4  will  show,  is  much 
higher  than  in  the  other  cuprammoniums  of  (H]uivalent  stn^ngth  in  i-oi^ 
per.  The  fact  coupled  with  the  difficulties  incident  to  the  prep^iration 
of  the  st<K»k  solution  hjis  sc»riously  militate<i  against  the  emplojnnent  of  the 
fungicide  »n  practice,  the  advantage's  incident  to  its  iLHt\  i.e.,  an  ailht*!*ivi*- 
ness  wpial  to  the  copper  sulphate  and  ammonia  wash'*  and  U»sser  injuri- 
ousness  to  the  grape,**  l)eing  not  sufficiently  comp<»nsator>'  to  outwf*i|^h 
the  dmwbacks. 

TABI.K  4 

Amount  of  ammonia  riquiud  to  ffiir  t Irar  solutions  of  the  ruprammttnium  ir«i«A/« 

irhrn  containing  0J)!M7  ftrr  cent  mrtallic  copjter 

NAMC  or  ruNoiriDr. 


( *op|MT-nmnioniii 

(\)|i|M>r  ((ulphiit<'«nnim(iniA 

(*np|M*r  xiilphato- iinirnoniuni  rHrl>onat4* 

Malnrhite-amnionia 

Hiirgimdy  niixture-ammc»nia 

Malafhitr-ntiimonium  rarbonatr . 

Hiiricuiiily  niixtun*-aninioniuni  carhonati* 


4MOr»T  NHi  BB4Jt  »«• 
TO  OIYB    %   iLBkB 

ptr  cent 

e  9772 

0  179 

0  OI9 

0  GMM 

•  ,ViO 

0  047 

0  aiH 

Hunjundy  mixture  and  ammonia.  This  the  ftarlii»st  copjier  carkNinate 
and  ammonia  wash  employe<l  in  practi(*e  wt&s  intnNluce<l  by  Patrigi^in 
in  1KS7**  and  coiL*<i.»*ts  simply  in  dissolving  th<'  ba»*ic  coppcT  carlNmate 
of  Burgundy  mixtun*  din'i'tly  in  the  mothcT  li(iuor  by  moans  of  am- 
monium hydn)xi<i.     The  w:ish  Ls  us<h|  to  some  extent  in  practice  and 

'•  Fo*\.  (1.     ("ourr*  roriiplct  dr  Vitirultiin*  ed.     4.    577. 
"  1 1»^\.  <1.     TXw  iMiiiu*.  p.  .'>7H. 

^*  I'ntrigroii.  (t.  Nouvraux  pHN'^l^  di>  tr»it4*m(*nt  dii  mildiou.  Journ.  m^- 
prat.  1;  s-sj.     ish7. 


1917] 


Butler:  The  Cuprammonixjm  Washes 


241 


is  known  in  the  United  States  under  the  name  of  modified  eau  celeste. 
The  formula  originally  proposed  was  as  follows: 

parte 

Copper  sulphate 1 

Sodium  carbonate 1.5 

Ammonia  sp.  gr.  0.9 0.769  by  volume 

Water  to *. 100      " 

Patrigeon's  formula  has  not  suffered  any  marked  modifications  at  the 
hands  of  the  various  authors  who  mention  it  as  will  be  seen  from  table  5. 

TABLE  5 

Strength  of  Burgundy  mixture-ammonia  and  corresponding  ratios  copper  sulphate 
sodium  carbonatCf  and  copper  suLphaie  ammonium  hydroxid  recommended  by  dif- 
ferent  authors 


BTRENQTH  IN  CX7PRIC  SULPHATE 

COPPER  SULPHATE 

RATIO    

SODIUM  CARBONATE 

COPPER  SULPHATE 

RATIO  

AMMONIUM  HTDROXID 

per  cent 

0.25 

1:1.20 

:0.83 

0.30 

1:1.25 

:0.83 

0.50 

1:1.25 

:0.83 

0.50 

1:1.25 

1.04 

1.0 

1:1 

:0.73 

1.1 

1:1.25 

:0.78 

The  amount  of  ammonia  called  for  in  the  various  formulae  for  the 
preparation  of  modified  eau  celeste  is  never  sufficient  to  give  clear  solu- 
tions. The  basic  carbonate  of  copper  of  Burgundy  mixture,  separated 
from  the  mother  liquor  by  decantation  is,  however,  readily  soluble  in 
ammonium  hydroxid,  as  may  be  gathered  from  table  6. 

TABLE  6 

Amount  of  ammonium  hydroxid  required  to  give  clear  solutions  of  modified  eau  cileste 


STRENGTH   IN  COPPER  SULPHATE 

AMOUNT  OP  AMMONIUM  HTDROXID 

REQUIRED  TO  GIVE  CLEAR 

SOLUTION 

STRENGTH   OF  SOLUTION  IN   NH| 

per  cent 

per  cent 

per  cent 

1.00 

4 

1.029 

0.50 

3 

0.772 

0.25 

2.5 

0.642 

0.10 

1.4 

0.360 

Burgundy  mixture  dissolves  in  ammonimn  hydroxid,  forming  cupram- 
monimn  hydrate  and  is  not  a  mixture  as  Chester^^  believed  of  cupram- 

"  Chester,  F.  D.    Report  of  the  Mycologist.    Delaware  Agr.  Exp.  Sta.  Rept. 
4:68.    1891. 


242  Phytopathology  (Vol.  7 

monium  hydrate  and  carbonate.  Modified  eau  o^leste  does  not  fcive 
jw.  to  malachite  on  decomposing  thus  indicating  absence  of  cupram- 
monium  carlx>nate.  When  the  wash  dries  upon  sprayed  foliage  the  cop- 
per is  deposited  as  an  hydrate,  mixe<l  with  some  sodium  sulphate  and 
bicarl>onate  unless  the  copper  carlx)nate  is  separated  from  the  mother 
lic]uor  and  levigated  l>efore  l)eing  di«<solved  as  is  sometimes  recommended. 

Copper  carbonate  and  ammonia.  The  copper  carbonate  and  ammonia 
wash,  or  ammoniacal  copper  carl)onate  was  introduced  by  Gasline''  and 
in  American  fungicide  literature  is  the  cupranunonium  most  commonly 
met.  with. 

Malachite  dLssolvos  in  ammonium  hydroxid  forming  a  solution  which, 
according  to  the  Duke  of  Be<lfonl  and  Pickering,'*  consists  mainly  of 
cupranunonium  cariM)nate,  while  (-hester*®  Lh  of  the  opinion  that  Inrth 
cupranunonium  carbonate  and  hydrate  are  forme<l.  As,  however,  the 
malachite  ammonia  wiish  dcM^s  not  deposit  malachite  on  standing.  I 
incline*  to  the  view  that  the  copper  is  pres4»nt  solely  as  cuprammonium 
hv<inite. 

Malnchit<»  (iissolv(\s  sparingly  in  anunoniurn  hydroxi<l,  the  total  amount 
entering  into  solution  lK»ing  l(»ss  in  a  strong  than  a  weak  concentrati<in 
of  ammonia.  P<»iuiy**  for  instance,  found  that  a  42.()8  per  cent  ammonium 
hvdn).xid  dLssolviHl.  imt  gram  weight  of  ammonia,  0.01329  grams  of  nHv 
tallic  co|)ixT  while  !ind<»r  similar  conditions  a  21.38  percent  solution  din- 
soIvchI  0.3132  grams  and  a  3.20  |K>r  cent  solution  1.063  grams  metallic 
i'opiMT  n*sjH»<»tiv(»ly.  The.s<»  results,  unfortunately  for  practice,  can  not 
Im>  obtaine<l  by  dis.Holviiig  a  given  (plant ity  of  malacliite  in  the  suitable 
corr<*s|)on<ling  strength  of  ammonium  hydn)xid.  In  order  to  obtain  the 
maxinnun  s<»lvent  action  it  Ls  nec<»ssar>'  to  us<»  a  ver>'  large  excesw  of  mala- 
chite, **even  five  fold  or  more"  which  int roduc(*s  ob vioas  difRculties  t hat 
can  not  Im»  tununl  cxct»pt  in  a  v(Ty  empirical  an<l  unsatwfactorj'  manner. 

The  malachite-anunonia  wjish  was,  {is  I  have  aln*ady  indicat<*<l,  pn>- 
|M>MMi  by  (fiistine  whos4»  formula  w:is  jis  follows: 


Mnlarhitr  .    .  0  M 

.Viiiiiiniiia  Kp    i^r.  n.lN)  ...       0  76U 

Watrr  to  .100 

Th(*  alK>v<*  fonnula  hit**  Imkmi  iiiorr  or   U'ss   m<Nlifi(Hl   at  the  hands  of 
subMH|U(*nt  writers,  as  will  W\  .»<4»<»n  from  table  7. 

'*  (iaMtiiK'.   i\.     Ijiiploi   <lij  f*:irlM»ii:it4*  aiitiiioiiianil  di*  cuivre  contfc*  Ip   pm>ni>* 
P|Hira      I*r«»([   agr   i-t  vit.  8:     1SS7. 

»\\i»lMirii  K\p    Fruit  I  ami  \U\>x    11:  JI       !«»I(I 

•     I  III*  ««arii«'.  p    ♦">>*. 

■>  rititix     ('     I.      'I'ljf  p-«paratiiin  nf  :tninii»iiiaral  miIiiIioii  of  ropprr  carlmiuilr. 
Dc'laman- Aier    l.xp   ."^la    Mill   22:  .'>      iyi:{. 


1917] 


Butler:  The  Cuprammonium  Washes 


243 


TABLE  7 

Strength  of  malachite^ammonia  wash  and  corresponding  ratioh  malachite:  ammonium 

hydroxid  recommended  by  different  authors 


STRKNGTH  IN  MALACHITE 

MALACHITE 

BATIO 

AMMONIUM    HTDROXID 

per  cent 

0.045 

22.2 

0.046 

5.5 

0.060 

12.8 

0.075 

11.3 

0.078 

:10 

0.078 

:13.2 

0.086 

:10 

0.093 

:8.7 

0.093 

:5.5 

0.097 

:10 

0.097 

:13.2 

0.100 

:1.23 

0.100 

:11 

0.125 

:8 

0.200 

:8 

Neither  in  the  original  formula  nor  any  of  the  subsequent  ones  that 
have  come  to  my  knowledge  is  the  ratio  malachite-ammonium  hydroxid 
such  as  to  insure  complete  dissolution  of  the  copper  salt.  In  order  to 
dissolve  the  malachite  completely,  at  least  within  a  reasonable  time,  the 
ratio  must  be  increased  to  1 :  30.  It  is  therefore  clear  that,  as  usually 
prepared,  the  wash  either  contains  less  copper  than  the  formulae  call 
for,  or  if  the  undissolved  malachite  is  incorporated  in  the  wash  then  the 
copper  will  be  placed  on  the  plants  partly  in  the  form  of  malachite  and 
partly  as  a  copper  hydrate.  In  order  to  obviate  these  difficulties  I  have 
employed  a  stock  solution  prepared  as  follows: 

parte 

Malachite t ? 1 

Ammonia  sp.  gr.  90 30  by  volume 

Water 20  by  volume 

In  preparing  the  stock  solution  water  must  be  used  as  otherwise  the 
solution  would  prove  unstable,  decomposing  %vith  formation  of  cupric 
oxid.  A  stock  solution  containing  as  little  as  five  parts  water  may  be 
prepared  and  probably  more  water  than  the  formula  calls  for  could  be 
used,  though  it  will  be  perfectly  obvious  that  there  is  no  object  in  making 
a  stock  solution  unduly  dilute.  In  fact,  ceteris  paribus  highly  concen- 
trated solutions  are  to  be  preferred. 

The  stock  solution  as  above  prepared  is  quite  stable  and  may  be  diluted 
very  considerably  without  decomposing,  but  contains  more  ammonia  than 


244 


Phytopathology 


(Vol.  7 


TABLE  8 

Amount  of  ammonium  hydroxid  required  to  ffive  cleat  nolulions  oj  maiarhiU* 

ammonium  hydroxid 


•TIIKKOTH   IN  TEBMi  OF 

corpftM  arLniATB 


prr  rent 
1 

0  5 
0  25 
0  10 


AMOUNT  AMMONIUM  HTOKOXIS 

MBQUIRBO  TO  UtVK  CLBAB 

•OLUTION 


ce. 

26  5 
13  '25 
6  {\2 
2  65 


•TBBNOTV  or  •OLTTION   IN    NHf 


6   82 

3  41 
1  70 
0.6S2 


mcNiified  eau  celeste  for  (Hjual  p<»rcoiitttg«s  of  copper  (Cu)  as  may  l>e  Hsen 
by  comparing  tahlo  8  with  table  (>.  Then^  is,  therefore,  no  just ifieat ion. 
since  sodium  sulpliate  and  biearlM)nate  are  not  injurioii:^  at  the  conrcm* 
trations  at  which  the  wjtsh  may  l)e  employed  in  practice,  in  the  preference 
aocordi^d  the  malachite-anunonia  wash,  as  the  (*opper  (M*curs  in  the  same 
fonn  in  Inith.  The  difTen»nce  in  favor  of  modifi(Ml  iiau  c^Uwte  is  n<it  only 
markcMi.  however,  in  the  fonniihu>  I  have  us<»d,  but  Is  also  favorable  to 
the  latter  wh(»n  w<»  comparer  \\u\  formulm^  of  authors.  Taking  the  ejc- 
tn»nM^  met  with  we  find  tlie  n«ults  shown  in  table  9  wliich  an*  even 
mon^  favonible  to  modified  eau  c^U^ste  than  in  the  case  of  my  fonnulae. 
And  when  we  consider  the  (^ost  of  the  unit  copper  employiHl  (exclasive 
of  lalK)r)  in  nuHlifi(Hl  eau  c^l(*ste  and  malachite-ammfuiia  we  obtain  a 
ratio  of  1:3  wliich  is  so  siKnifi(*ant  as  to  n^iuin^  no  comment. 

TABLK  9 

Extrrmr  jterrrutagrtt  of  ammnuin  nut  with  in  thr  Utrmidae  of  author*  for  the  ffrefiaro-' 
tiou  of  numiifitd  rait  n'lrHtt   *  A  )  and  mat ac hit i -ammonia  \H\  renpertirtty 


•TRrMiTM   Of  HOLI^ION    IN 

TKBMM  or  rorrcH 
■I  Lrn  «TC 


per  ttnt 
0   J.") 


1    1 


nTKKM 

iTH 

OF 

MiLi-ri«».M 

iM 

NH* 

A 

\ 

B 

prr  rrnt 

ptremni 

0  051 

: 

0  554 

0  (»73 

0  141 

0  joi; 

0  707 

CI  JIM 

2  S2S 

t'.   t'liprntntnitnium  cnr^Httuitf    wnshrs 

< 'upniiniiKiiiiuni  carlNiiiatc  \\:i^h(•^  an*  foriiuNl  when  cupric  sulphate, 
ni:il:i<*)iiti*.  rupraniiiifinMim  >ulph:it<*  '('uSn4.  -|  Nils.  H3O)  and  the  Imisic 
cupn«'  *:irlM»iiai<*  nf  HurKuiidv  tnixtun'  an*  ilirv-olvnl  in  runmoniuni  car- 
ImukiIi  MMf<  t);  MI4.  NH,<'n,  .  Till-  \\a>h«-^  an»  ver>'  sUble.  the 
nMi>t   «t:tii|i-  III   till*  riipraiiiiit«>iiiuni  fun^icidi*^.  only  decom|M)sinK  slowly 


1917] 


Butler:  The  Cuprammonium  Washes 


245 


on  long  standing  with  formation  of  malachite.    When  the  washes  diy 
on  sprayed  foliage  the  copper  is  deposited  as  a  carbonate. 

Cuprammonium  suiphcUe-amm^mium  carbonate.  This  wash  was  in- 
troduced by  the  United  States  Department  of  Agriculture  in  1890** 
under  the  name  of  mixture  number  5  but  has  never  been  used  to  any  ex- 
tent in  practice  as  it  was  not  found  to  possess  a  lesser  toxicity  than  other 
cuprammoniums  and  is  not  economical  to  prepare.  The  formula  origi- 
nally proposed  was  as  follows: 

porta 

Ammoniated  copper  sulphate  (Cuprammonium  sulphate) 0.21 

Ammoniiun  carbonate 0. 12 

Water  to 100 

Malachite-ammonium  carbonate.  This  fungicide  was  introduced  by 
Chester**  in  1891  as  a  substitute  for  the  malachite-ammonia  wash,  but 
despite  manifest  advantages  has  been  but  Uttle  used  in  practice.  Ches- 
ter's formula  is  as  follows: 

parts 

Malachite 0.052-0.058 

Anmionium  carbonate 0.27  -0.31 

Water  to 100 

The  original  formula  has  been  modified  to  some  extent  by  subsequent 
writers  as  i^  shown  in  table  10. 

table  10 

Strength  oj  malachite-ammonium  carbonate  wash  and  corresponding  ratios  malachite: 

ammonium  carbonate  recommended  by  different  authors 


MALACHITK 

STRSNOTH  IN   1IA.LACHITE 

AMMONIXTll    CARBONATK 

percent 

0.039 

1:6 

0.046 

1:5.3 

0.052 

1:5.19 

0.058 

1:5.34 

0.066 

1:3.3 

0.093 

1:5.3 

Malachite  dissolves  fairly  readily  in  ammonium  carbonate,  carbon 
dioxid  and  a  little  ammonia  being  evolved  during  the  reaction,  but  the 
reaction  is  not  sufficiently  rapid  nor  the  conditions  under  which  it  takes 
place  such  as  to  permit  the  preparation  of  the  fungicide  as  required.  A 
stock  solution  is  necessary  and  may  be  conveniently  prepared  as  follows: 

«  United  States  Department  of  Agriculture  Rept.  1890:  402. 
»  Delaware  Agr.  Exp.  Sta.  Rept.  4:  71.     1891. 


246 


Phytopathology 


[Vol.  7 


Malachite 1 

Ammonium  carbonate  (hard)** 3 

Water 30 

Place  the  malachite  in  a  suitable  non-metal  vessel,  add  the  amnionium 
carbonate  in  small  pieces,  and  then  the  water.  Warm  gently  and  mb 
soon  as  effervescence  bepns  remove  from  flame  and  stir.  Let  Ktand  a 
few  minutes,  place  back  on  flame  and  continue  as  before  until  on  wann* 
ing  fi^ntly  no  further  effervescence  takes  place.  The  vessel  should  thiro 
be  closed  and  set  aside  until  the  malachite  has  completely  disHolved, 
should  it  not  already  have  done  so.  The  stock  solution  prepared  as  aljove 
will  withstand  marked  dilution  without  a  further  addition  of  anunonium 
earl)onate  I>eing  require<l  at  least  within  the  ranfi^e  of  concentration  in 
coppcT  that  I  liave  used,  as  will  lx»  seen  from  table  11. 


TABLE  11 

Amount  of  ammonium  carbonate  {hard)  required  to  give  clear  ttolutionn  of  malarhitf 

ammonium  carbonate 

n'RKNOTM    IM 

AMOt'NT   AMMOMCM 

(-\HBONATE    NKgriHKb 

TO   ur\'K    A  (LJCAM 

IM»LrTION 

HALAcnrrK 

STRCffOTII   or  IMILC- 

MAi.4rHnrB 

AMMONIt'M    C'AKBONAnC 

TioM  m  NH* 

prr  rtmt 

prr  ctnt 

^tretmi 

0  .V) 

1  5 

1:3 

0  476 

0  JO 

0  f) 

1:3 

0  19U 

0  10 

0  3 

1:3 

0  oas 

0  o:> 

0  15 

1:3 

0  047 

Copper  Hulphaie  and  ammonium  carbonate.  The  coppt;r  sulphate  and 
anunonium  car)K)nate  wash  known  in  Anu^rican  literature  as  Johnson'^ 
mixtun;  has  lHM»n  but  little  uschI  in  pnictic(»  an<l  Is  but  ran»ly  mentione^i 
by  writers  on  the  funfci<'idi*s.  The  wiu<h  was  first  dtwcrilKid  in  18!U  by 
J(>hns<»ir*  who  profKiMHl  the  following  formula  for  its  preparation: 


(NjpJMT  Htllphfld' 

Ariiiiioniuin  riirlK»iiiiti>  (hard) 
(ir  Ariifiioriiiiin  rnrlNtrmtr  'Htift  ) 
WfttiT  to   .    .    . 


0 

1 

0 

21) 

0 

23 

1(10 

'*  Aiiiiiiofiiiiiii  rarUtiiatc  diM^oiii^MiW!*  (»ri  cxpoHurc  tf>  nir  ami  in  prrparinfc  th<*  M«K*k 
iu>ltitii>n  th«'  atiiiiunt  of  thr  Halt  ii^mmI  will  have  (o  U>  incroamHl  unirm  it  ia  in  prr- 
f«M  tly  hard  tranNlurrnt  platrH.  \\  hrn  romplft<>ly  df'<*oniiM»m>d  ammonium  rarlKinjite 
ocriirH  lis  an  o|Ktc|uc  ihiwiIit  and  wh<*n  in  thin  romlition  the  amount  railed  for  in 

tli«-  fi*niitl]a  ^h(lllld  U*  dollhlrd. 

"  Jnliiit^oii,  S  \V  Noll'  l»y  ihf  Dirertor.  ConniM'tirut  A^r.  Kxp.  Sla.  Kept. 
1890:113      iy«l. 


1917] 


Butler:  The  Cuprammonixtm  Washes 


247 


Johnson's  mixture  is,  next  to  the  copper  sulphate  and  ammonia  wash 
(eau  celeste),  the  most  easily  prepared  of  all  the  cuprammoniums.  When 
anmioniimi  carbonate  is  added  to  a  strong  solution  of  cupric  sulphate  a 
precipitate  is  first  formed  accompanied  by  effervescence  due  to  the  lib- 
eration of  carbon  dioxid  which  on  a  further  addition  of  ammoniimi  car- 
bonate promptly  and  completely  dissolves  even  in  the  cold. 

Johnson's  mixture  forms  very  stable  solutions  and,  as  a  glance  at  table 
12  will  show,  is  for  equivalent  of  copper  compositionally  identical  with 
malachite-ammonium  carbonate. 

TABLE  12 

Amount  of  ammanitan  carbonate  hard  and  soft  required  to  give  clear  solutions  of  John' 
son's  mixture  and  corresponding  ratios  cupric  sulphate:  ammonium  carbonate 


■TBXNOTH  IN 

AMOUMT  AMMONIUM  CABBONATE 

BSQUIBND  TO  OIVB  A  CLBAR 

■oxjUTIom 

CUPRIC  SULPHATE 

STRENGTH 
or  SOLUTION 

IN  NHt^ 

PHATB 

AMMONIUM  CARBONATE^ 

Hard 

Soft 

P€reerU 

percent 

percent 

percent 

1.00 

1.56 

2.40 

1:1.56 

0.495 

0.50 

0.78 

1.20 

1:1.56 

0.247 

0.20 

0.31 

0.48 

1:1.56 

0.099 

0.10 

0.15 

• 

0.24 

1:1.56 

0.049 

^  Refers  to  solutions  prepared  with  undecomposed  ammonium  carbonate. 

Burgundy  mixture-amnumium  carbonate.  Burgundy  mixture  may  bo 
readily  dissolved  in  ammonium  carbonate  3delding  a  cuprammonium 
very  similar  to  those  obtained  with  malachite,  copper  sulphate,  or  cupram- 
moniiun  sulphate  as  will  be  seen  by  a  glance  at  table  13. 

TABLE  13 

Amount  of  ammonium  carbonate  required  to  give  clear  solution  of  Burgundy  mixture- 
ammonium  carbofKUe  and  corresponding  ratios  Burgundy  mixture:  ammonium  car- 
boncUe 


BTRENOTH  IN  COPPER 
SULPHATE 

AMOUNT  AMMONIUM 

CARBONATE   (HARD) 

REQUIRED  TO  OnTE   A 

CLEAB  SOLUTION 

BUBGUNDT   MDCTUBB 

BATIO  

AMMONIUM    CARBONATE 

STBENGTH  OP  SOLU- 
TION IN  NHs 

percent 

percent 

percent 

1.00 

1.20 

1:1.20 

0.380 

0.50 

0.60 

1:1.20 

0.190 

0.25 

0.30 

1:1.20 

0.095 

0.10 

0.12 

1:1.20 

0.038 

The  data  given  in  table  13  are  for  a  Burgundy  mixture  in  which  the 
ratio  copper  sulphate  sodium  carbonate  (crys.)  was  1: 1.84,  and  the  pre- 
cipitate was  separated  from  the  mother  liquor  before  dissolving  in  the 


248  Phytopatholoot  [Vol.  7 

ammonium  carbonate.  In  practice,  however,  the  precipitate  would  not 
need  to  be  separated  from  the  mother  liquor,  since  the  salts  therein  con- 
tained are  not  injurious^  at  the  concentrations  at  which  the  wash  may 
be  employed  in  practice. 

As  a  result  of  our  study  of  the  properties  and  preparation  of  the  cupram- 
moniiun  washes  we  may  conclude: 

1.  The  cuprammonium  carbonate  washes  are  the  most  stable  and  for 
strengths  in  metallic  copper  of  0.14  per  cent  or  less  require  less  ammonia 
to  give  clear  solutionis  than  the  washes  prepared  with  ammonium  hydroxid. 

2.  The  copper  salts  dissolved  in  ammonium  carbonate  3rield  washes 
in  which  the  active  principle,  i.e.,  the  copper  is  in  the  form  of  a  carbonate. 

3.  Metallic  copper,  malachite,  and  the  basic  carbonate  of  Burgundy 
mixture  form  cuprainnionium  hydrates  when  dissolved  in  ammonium 
hydroxid  modifie<i  eau  c^K^e  requiring  pvir  equivalent  of  copper  the 
least  amount  of  solvent. 

4.  Cupric  sulphate  forms  with  ammonium  hydroxid  a  cupraiiunonium 
sulphate  which  Is  the  least  stable  of  the  cuprammonium  fungici<ics. 
though  less  anunoiiia  b<  required  to  give  a  clear  solution  than  in  the  case 
of  the  niprammoniiun  hydrates. 

II.    RELATIVK   TOXICITY   OF   THE   CUPRAlfMO.VIUM    WASHES 

The  cuprammonium  washes  may  l)e  toxic  to  the  sprayed  plant:  {D 
Between  the  time  of  application  and  time  of  drying;  (2)  after  dr>nng 
owing  to  dissolution  of  the  contained  copper  on  weathering;  or  (3)  the 
injur>-  pnxluced,  if  any,  may  l)e  the  result  of  the  additive  effect  of  1  and 
2.     Thon^  lin'i  no  other  possibilities. 

A.  Effect  of  the  cuprammoniuffm  on  planta  between  the  time  of  applicaiian 

and  the  time  of  drying 

It  will  Ix)  at  once  evident  that  if  the  cuprammoniums  nuule  with  ammoo- 
iuiii  hy<in>xid  owe  their  toxicity  to  the  presence  of  anunonia,  the  toxic 
action,  owing  to  the  rapid  dis.sipalion  of  ammonia  in  the  interim  lietwec^ 
time  of  application  when  its  con(*ent ration  will  Ina  highest  and  time  of 
d<*>i(vation  when  its  conci^ntnition  H-ill  \)o  zero,  must  and  can  only  take 
phi«*<*  during  the  ilrying  of  the  .^pray.  Ammonium  carbonate  bt  lev 
vol.'itilc  than  junmoniuni  hydroxid,  but  nevertheless  decomposes  readily 
on  rx|H»sure  to  air  and  has  vani.shc<l  when  the  wiishes  of  which  it  is  a  com- 
ponent have  dritni  u|K)n  the  foliage,  hen<*<*  injur>'  due  to  the  presence  of 
ainin«iiii:i  in  ainn ionium  ciu'lMmate  can   also  only  In^  produced   in  the 


1917] 


Butler:  The  Cuprammonium  Washes 


249 


o 
o 


00 

o 


Si 


M 
O 

•-a 


f  S 

O) 

6 


9 
O 

1a 

S 

Pk4 


§ 


k^ 


OC^O«0'^1^00 


00 

■ 

o 

SC                'H              d     »-(     1-1 

• 

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250  Phytopathology  [Vol.  7 

* 
interim  between  time  of  application  and  time  of  drying.    If  the  toxic 

action  is  due,  on  the  other  hand,  to  noluble  copper  or  ammonium  sulphate 
whenever  this  Halt  occurs,  then  the  injury  resulting  may  be  produced  dur- 
ing the  time  of  drying  and  also  at  such  sul)sequent  times  as  the  fungicide 
is  wetted  by  meteoric  water.  The  rate  at  which  the  cuprammoaiums 
dry  upon  sprayed  foliage  will,  it  may  therefore  be  presumed,  have  a  very 
marked  effect  on  the  degree  of  injury  produced.  And  in  fact  experimental 
evidence  fully  confirms  the  presumption  as  is  shown  in  table  14  and  plates 
III  and  IV. 

The  data  presented  in  the  above  table  show  how  significant  was  Audoy- 
naud's  reconmiendation  that  the  copper  sulphate  and  ammonia  wash 
be  applic<l  during  dr>%  wann  weather  and  fully  justifies  Bourcart*.^'^ 
statement  that  scorching  '*is  especially  to  he  feared  when  eau  c^Ie:<te  i^ 
applied  during  moist  weather  and,  coni^c<}uently,  when  it  dries  slowly  on 
the  leaves;**  but  that  on  the  other  hand  ''when  the  spray  is  applied  <lur- 
ing  the  hot  days  of  summer,  this  fault  disappears  entirely,  and  eau  c*elf^te 
possesses  nothing  but  advantages.*'  The  data  presented  in  the  table 
show  conclusively  that  slow  drying  is  much  more  injurious  than  quirk 
drying,  the  difference  l)eing  ver>'  striking  indeed  in  the  ca**e  of  malachite- 
ammonia  and  malachite-ammonium  carbonate  containing  0.28  per  cent 
and  0.14  per  cent  copper. 

While  the  data  prosente<l  in  table  14  show  that  whenever  a  cuprain- 
monium  is  toxic  it  is  invariably  more  injurious  when  drieil  slowly  im^ 
spective  of  the  plant  spmyetl,  it  does  not  give  us  any  ver>'  definite  infor- 
mation regarding  the  cause  of  the  deleteriousness  of  these  washes.  The 
data  do  not  supiN)rt  conclusively  either  the  view  that  aimnonia  is  the 
toxic  agent,  or  the  view  that  the  toxicity  is  due  to  soluble  copper  since 
were  but  one  of  tlu»sc^  conijKments  tin*  sole  cause  of  the  injur>'  protluccti  a 
certain  proportionality  would  exist  differing  only  in  degree  in  different 
plants  lM!tw(H'n  a  given  strength  of  the  toxic  Kul»stance  and  the  resulting 
mjur>',  but  a  considenition  of  table  14  shows  that  no  such  relation  exists 
in  cither  c]is4*.  On  the  other  han<l,  the  data  clearly  show  that  ammonium 
sulphate  do«rs  not  |K)ssi*ss  luiy  niark<Mlly  injurious  properties.  Neither 
an*  the  malachite  wa*<hes  shown  to  In'  K^s  injurious  than  those  maiie 
fn»in  cupric  sulphate  and  auuiionia.  a  fact  worthy  of  S4*rious  consiiiera- 
tion  in  view  of  the*  general  abandonment  of  the  latUT  cm  account  of  sup- 
fjosiil  gr«iter  toxicity. 

Hut  siiKM*  nu  individual  coin]Minent  of  the  cupranimoniuni  wa*«h«*s  is 
apiMin-ntly  inr  x#  the  mn^r  of  the  toxie  action  pnKluce<l  in  the  inteival 
lx*twe(  n  thf-  applieatjnn  of  th«>  fungirid«>  and  its  desiiraticm  it  will  U* 

•    liourrnrt.  K       I^-h  iiiii1:m!i»'<  «!«f  plant h.  .'JTii.     Pnrirt.      W^U). 


1917)  Bdtlbb:  The  Cuprahhoniuh  Washes  251 

necessary  for  us  to  study  their  behavior  when  applied  separately  in  order 
to  interpret  the  data  ^ven  in  table  14,  and  to  the  action  of  soluble  copper 
we  may  well  devote  attention  first. 

The  only  suitable  copper  salt  to  use  in  studyii^  the  effect  of  soluble 
copper  when  applied  in  the  form  of  &  spray  is  cupric  sulphate  and  since 
the  acid  radicals  of  the  copper  salts  are  not  in  themselves  injurious*"  the 
toxicity  of  cupric  sulphate  may  be  considered  as  due  to  the  copper.  Sol- 
uble copper  is,  as  is  well  known,  extremely  toxic  to  vegetation  and  we 
would,  therefore,  expect  that  the  injury  produced  by  an  application  of 
cupric  sulphate  would  be  the  greater  the  slower  the  spray  dried  on  the 
foliage,  and  the  data  presented  in  table  15,  fully  confirm  this  expectation, 
and  the  illustration  shown  in  plate  V  is  no  less  emphatic. 

TABLE  IS 

Effect  of  quiek  and  tlow  drying  on  the  loxieity  of  cupric  tulphate  eijtreued  in  per  cent 
of  injury 


>  The  beading,  used  also  ia  plate  viii,  means  that  the  percentage  strength  of  the 
solution  ie  given  in  terms  of  milligrams  iastead  of  fractions  of  a  gram. 

The  data  presented  in  table  15  and  shown  graphically  in  plate  VIII 
indicate  that  the  tomato,  Oxalis,  bean  and  cauliflower  are  much  more 
sensitive  to  soluble  copper  than  either  the  Coleus  or  the  Pelargonium. 
The  tomato,  bean,  Oxalis  and  cauliflower  respond  in  a  somewhat  simitar 
mamier  to  soluble  copper,  the  curves  for  quick  and  slow  drjii^  being 

"  Bedord,  Duke  of,  and  Pickering,  S.  U.  Woburn  Experimental  Fruit  Fann 
Kept.  11:    1910. 

Clark,  J.  F.  Oa  the  toxic  properties  of  some  copper  compouods  with  special 
refereoce  to  bordeaux  mixture.    Bot.  Gaz.  33:  39.     1902. 

Hawkins,  L.  A.  The  influence  of  calcium,  magneBium  and  potaaalum  nitrates 
upon  the  toxicity  of  certain  heavy  metals  towards  fungus  spores.  Physiological 
Researches  1:  S7.    1913-16. 


252 


Phytopathology 


[Vol.  7 


ver>'  nearly  parallel  at  the  higher  concentrations.  In  the  case  of  the  cauli- 
flower which  is  very  sensitive  to  soluble  copper  the  curves  are  nearly 
proximate,  while  in  the  case  of  the  tomato,  which  is  much  more  tolerant, 
they  are  distant.  The  curves  for  the  Oxalis  and  bean  are  very  similar 
in  character,  and  resemble  those  of  the  tomato,  though  the  bean  is  more 
sensitive  to  soluble  copper  than  the  Oxalis  and  the  Oxalis  less  resistant 
than  the  tc^mato.  In  the  most  highly  resistant  plants  studied,  the  Pelaricrv 
nium  and  C'oleus,  the  curves  show  marked  similarity,  the  to:;icity  on  slow 
dr>'ing  increa«<ing  a  little  more  rapidly  in  the  former  than  in  the  latter. 
It  will  also  be  noticed  that  while  in  the  more  resistant  plants  ((*o!eua« 
Pelargonium)  the  toxicity  is  practically  proportional  to  the  concentratioo 
in  the  less  resistant  plants  proportionality  ceases  to  exist  as  scMin  as  the 
threshold  of  toxicity  is  appn  ached,  the  decrease  l>eing  much  more  rapid 
than  the  data  for  the  higher  cxincentrations  would  lead  one  to  anticipate. 
The  practical  importance  of  these  facts  will  escape  no  one. 

TABI.F  16 
Effect  of  hIow  nrui  quick  druiug  on  the  toxicity  of   ammtmi um  hti<iroTid   ■/».  gr.  90, 

eTjrreiitted  in  fnr  cent  of  injury 


\  ANIKTT    mtV 


HOW 
DNIKD 


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0  51 


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(^uirkly 
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(^Uiirkly 
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Thr  t<»xi<*ity  of  :iiiiiiH»niuiii  hy(ln>xid  h:is  Ih»<mi  ronsi<len»d  higli  by  all 
writers  who  have  h<»ld  the  t<»nct  that  the  toxi<*ity  of  the  copp<»r  ami  am- 
monia wastu's  was  due  to  th«*  amiiionium  hydroxid  though  MillanlH 
|)oure«|,  he  tells  us.  stnmg  aiiimonium  hydroxid  on  the  foliagf^  of  the  grafie 
without  pHMlucing  injur>'.  a  result  >tn>ngly  (Mintradicting  the  prevailing 
vi(*w.  and  the  data  pn>ent<sl  in  table  Ki  are  not  on  analysis  favorabh*  to  it. 

A  glanrc  at  the  table  revrals  that  like  the  cuprannnoniums  and  ruphc 
sulphate*  aniinoniuin  hydroxid  even  though  highly  volatile  is  nmch  UMkn* 
t4»\ir  when  dri«»<l  slowly  and  the  illustnition  given  in  plate  VI  sh*»ws 
verv  "^trikinglv  what  marked  differences  mav  Ik*  obtaineit.  The  tfata 
al*4»  sh<»w  that,  of  all  the  plants  us4<l,  the  tomato  is  the  most  sensitive 


1917] 


Butler:  The  Cuprammonium  Washes 


253 


to  ammonium  hydroxid  while  the  Coleus,  bean  and  cauliflower  follow  in 
increasing  order  of  resistance.  Now  if  ammonium  hydroxid  is  primarily 
the  cause  of  the  toxicity  of  the  cuprammoniums  of  which  it  is  a  compo- 
nent part  the  relative  resistance  of  the  plants  when  sprayed  with  the 
copper  sulphate  and  ammonia  wash  or  the  malachite-ammonia  wash 
should  remain  imchanged.  In  reality  we  find  that  when  the  former  is 
employed  the  sensitiveness  of  the  plants  is  in  decreasing  order  as  follows: 
Tomato,  bean,  Coleus;**  and  when  the  latter  is  used  that  it  is  as  follows: 
Tomato,  Coleus,  bean.  The  evidence  is  therefore  clear  that  anunoniiun 
hydroxid  is  not  the  primary  cause  of  the  toxicity  of  the  cuprammoniums. 
The  toxicity  of  ammonium  hydroxid  is  of  course  due  to  the  ammonia 
(NH3)  it  contains  and  it  would  therefore  be  expected  that  ammonium 
carbonate  which  has  been  used  in  the  preparation  of  cuprammonium 
washes  would  also  prove  injurious  since  while  less  volatile  and  alkaline 
than  the  former  it  nevertheless  decomposes  rapidly  on  exposure  to  the 
air  with  liberation  of  ammonia  and  carbon  dioxid.  And  in  fact  experi- 
mentation shows  ammonium  carbonate  to  be  much  more  toxic  than 
usually  supposed  as  will  appear  from  a  consideration  of  table  17. 

TABLE  17 

Effect  of  slow  and  quick  drying  on  the  toxicity  of  ammonium  carbonate,  expressed  in 

per  cent  of  injury 


▼  ABIETT  U8XD 


Coleus "j 

Tomato < 

Cauliflower 

Bean 


STRENGTH  OP  SOLUTION   IN   NHj 


HOW 
DRISD 

1.90 

0.05 

0.47 

0.23 

percent 

percent 

percent 

percent 

per  cent 

per  cent 

per  cent 

per  cent 

Quickly 

40 

2 

0 

0 

Slowly 

100 

81 

0 

0 

Quickly 

40 

15 

5 

0 

Slowly 

100 

70 

50 

20 

Quickly 

75 

29 

10 

7 

Slowly 

92 

42 

13 

6 

Quickly 

1 

0 

0 

Slowly 

8 

0 

0 

The  data  presented  in  table  17  and  more  strikingly  illustrated  in  the 
graphs  (plates  IX  and  X)  show  that  within  the  limits  of  toxicity  ammonium 
carbonate  is  much  more  injurious  per  equivalent  of  ammonia  than  am- 
monium hydroxid  and  it  is  rather  diflicult  to  understand  how  it  could 
ever  have  come  to  be  considered  less  noxious  than  the  former.  As  would 
be  expected  from  the  nature  of  the  salt,  the  toxicity  of  ammonium  car- 


*<»  The  cauliflower  was  not  used  in  the  experiments  on  the  toxicity  of  the  cupram- 
moniums. 


264  Phytopathology  [Vol.7 

bonate  when  dried  slowly  is  much  more  marked  than  when  it  is  dried 
quickly.  The  illustration  (plate  VII,  fig.  1),  will  show  what  striking 
effects  may  be  obtained. 

The  data  show  that  of  all  the  plants  studied  the  tomato  is  the  most 
sensitive  to  ammoniimi  carbonate,  the  susceptibility  of  the  other  plants 
being  in  order  of  increasing  resistance  as  follows:  Coleus,  cauliflower, 
bean.  Similarly  in  the  case  of  ammonium  hydroxid,  the  relative 
susceptibility  of  the  plants  is  in  increasing  order  as  follows:  Tomato, 
Coleus,  bean,  cauliflower.  The  relative  toxicity  of  ammonium  hydroxid 
and  ammonium  carbonate  is  clearly  shown  in  plates  IX  and  X.  An  in- 
spection of  the  graphs  on  these  plates  shows  that  the  toxicity  of  am- 
monium carbonate,  whether  dried  quickly  or  slowly,  increases  much  more 
rapidly  with  the  concentration  than  does  the  toxicity  of  ammonium 
hydroxid,  the  curves  for  the  former  indicating  proportionality  between 
concentration  and  toxicity  while  those  for  the  latter  resemble  those  given 
by  copper  sulphate.  A  consideration  of  plate  IX  shows  that  ammonium 
carbonate  is  more  toxic  to  the  bean  and  cauliflower  irrespective  of  the 
rate  at  which  dried  than  ammonium  hydroxid.  From  plate  X,  on  the 
other  hand,  we  gather  that  in  the  case  of  the  tomato  ammonium  carbon- 
ate is  less  toxic  between  0  and  0.95  per  cent  ammonia  than  ammonium 
hydroxid  when  dried  quickly,  but  is  invariably  more  toxic  when  dried 
slowly;  in  the  case  of  the  Coleus  ammonium  carbonate  dried  quickly  is 
less  toxic  between  0  and  1.02  per  cent  ammonia  than  ammonium  hy- 
droxid and,  when  dried  slowly,  less  toxic  between  0  and  0.51  per  cent. 

Ammonium  sulphate  has  been  considered  by  certain  writers  as  the 
toxic  agent  of  the  cuprammoniiuns  in  which  it  occurs  and  the  copper 
sulphate  and  ammonia  wash  has  suffered  relegation  in  consequence  of 
this  view.  Pearson,'®  however,  at  an  early  date  impugned  this  belief 
for  he  found  that  the  mother  liquor  of  a  strong  copper  sulphate  ammonia 
wash  caused  no  injiuy  to  the  grape  vine,  the  strawberry  and  "various 
other  vegetables."  A  glance  at  table  18  will  show  that  ammonium  sul- 
phate can  not  possibly  be  the  cause  of  the  toxicity  of  the  cuprammoniums 
in  which  it  occurs,  since  the  amoimt  of  ammoniiun  sulphate  formed  could 
not  exceed  0.53  gram  for  every  gram  of  cupric  sulphate  employed.  But 
if  ammonium  sulphate  can  not  be  the  cause  of  the  toxicity  of  the  copper 
sulphate  and  ammonia  wash  or  Johnson's  mixture,  the  data  presented 
in  the  table  show  that  it  possesses  a  peculiarity  to  which  we  may  well 
devote  a  moment's  attention. 

"  Pearson,  A.  N.  In  Report  on  the  experiments  made  in  1888  in  the  treatment 
of  the  downy  mildew  and  blackrot  of  the  grape  vine.  U.  S.  Dept.  Agr.,  Sec.  Veg. 
Path.  Bui.  10:  18.     1889. 


1917] 


BcTLEs:  The  Cupiluiuonidh  Washes 


BS*et  0/  flew  a*d  quick  ttryitin  on  tht  loneily 

per  cent  of  injury 


$vtpfuiU,  erpratttd  tn 


■• 

euin 

™>,«n.o,^„.o- 

4p««Dt 

Iperont 

lp««t 

0.1  p««i» 

Col.«. 1 

B..„ / 

Quickly 

Slowly 
Quirkly 
Slowly 
Quickly 
Slowly 

91 
24 
63 
25 
73 
SO 

19 
28 
4 
34 
22 

24 
0 

16 
1 
8 
6 

0 
0 
0 

TooMto 

{ 

0 
0 

Bfftett  on  tomato,  CoUvt  and  btan  of  the  mIowIj/  dried  euprawimonimiu  and  their  eom- 
ponenli  <U  the  $lr^nftht  at  trhich  Ihey  occur  in  the  ictuhei,  txprtiud  in  per  cent  of 


256  Phytopathology  (Vol.  7 

Amnionium  tmlphute  is  more  toxic  when  drieci  quickly  than  whrn 
drietl  slowly,  beha\ing  in  this  respect  exiietly  the  reverse  of  the  other 
components  of  the  cuprammoniums  all  of  which  are  much  more  toxic 
when  dried  slowly.  The  injur>'  pro<luce<l  by  quick  dr>ing  may  \x*  vvry 
markcKl  and  the  illustration,  plate  VII,  fig.  2,  will  add  but  emphasis  to  thf 
striking  figures  in  the  table.  The  explanation  of  this  peculiarity  is  that 
ammonium  sulphate  is  slightly  hygroscopic  and  when  dried  quickly  with- 
draws water  from  the  leaf  which  vnlt»  and  dies,  but  that  when  drietl 
slowly  equilibrium  lx»tween  the  c(»lls  of  the  e])id(»rmis  and  the  solution  is 
r<»ache<l  by  the  time  dr\'ing  begia**. 

The  plant  most  scTiously  injunnl  by  quick  (lr>iug  is  the  (\>leus,  then 
follows  the  lM»an,  the  tomato  Ixing  but  littl<»  more*  seriously  afTert^l  by 
quick  dr>'ing  than  by  slow  dr>'ing,  the  data  for  1  per  cent  solutions  beinK 
in  this  respect  particularly  ia»«tnictive.  It  would  ap|M»ar  then»fore  that 
the  cutirl(»sof  the  Coleusand  b(»an  are  not  reacHly  iKTineatiMl  by  ainni«>- 
niuin  sulphate  while  that  of  the  tomato  is  easily  iM'netnite<l  which  farts 
are  of  cdnsidrrable  inten'st  since  slow  drj'ing  which  pVoiM»rly  nu^asuroA 
the  toxicity  of  the  salt  shows  that  the  most  readily  iH*netrat<Hl»  leaf  is 
also  the  most  siiscei)tible. 

Having  conchuled  our  study  of  th(;  com])onents  of  the  cuprammoniums 
we  are  in  a  [)ositiou  to  determine  the  nature  of  their  role  in  the  toxicity 
of  tht»s4'  washes.  In  order  to  simplify  our  stu<ly  I  havt»  placinl  en  regard 
in  tabh»  19  the  iMTcentage  injuries  pro<luc(Hl  on  the  one  hand  by  the 
M»Vfral  cupranunoniums  and  <»n  th<*  other  the  injur>'  that  wouhi  have 
followe<l  the  us<*  of  the  com]>on<nts  at  the  corresiMinding  strengths  at 
which  they  <M*cur  in  the  washes,  the*  data  being  in  all  cases  for  slow  ilr>'ing. 

The  data  prrM-nttnl  in  the  tnblr  confirm  in  large  measure  the  \ifw  of 
Millardet  that  solubU*  copp<T  is  the  cauw*  of  the  injur>'  pnHluce<i  by  the 
cupranmioiiiums  though  it  would  also  apix*ar  that  anunonia  lH*c«)mes 
toxir  when  its  con(*entration  excetKls  an  amoimt  thiit  may  or  may  not  \^ 
consiiliTably  in  exci'ss  of  that  normally  tolerati^l  by  the  plant  amcirniil. 
For  instance  in  the  cas<'  of  the  Coleus,  malachiti'-ammonium  carlK»n:it«» 
containing  ().2S7  imt  cent  copper,  is  more  toxic  than  the  i^quivalt-nt 
strength  of  S4)lubli'  copfHT  or  ammonia  whence  it  must  Im*  c<mclu<h*tl  that 
the  injury  is  due  to  coinbim^l  action  of  thr  two;  and  it  would  appear 
fn»ni  thr  behavior  of  this  wash  at  other  strengths  that  the  pn's«nri'  of 
aimu<»nia  has  in  all  ras<*s  even  when  its<'lf  not  apparently  tiixic.  increas«il 
the  toxicity  <;f  the  copi>er.  The  malachit4'-amm(mium  carUinate  wash 
aUo  ^hn^l*<  evidi  nr«'  of  an  a<lditive  effect  except  at  the  hiwest  concentra- 
tion U'^mI.  (Ml  the  other  hand.  Johns<m*s  mixture  shows  that  the  t4>xicity 
of  snlubl*  eiipiM  f  i^  re<liired  by  it<  presence  despite  the  fact  that  the  c<»n- 
centration  of  aniiii«  nia  is  verv  nearly  the  sjime  as  in  malachite-amnii>- 


1917]      ^  Butler:  The  Cuprammonium  Washes  257 

nium  carbonate;  but  in  the  case  of  the  copper  sulphate  and  ammonia 
wash  the  evidence  is  conflicting.  When  we  come  to  consider  the  tomato 
we  find  that  the  presence  of  ammonia  reduces  the  toxicity  of  soluble 
copper  in  the  case  of  Johnson's  mixture  and  the  copper  sulphate  and  am- 
monia wash,  but  that  in  the  malachite-ammonia  wash  its  toxicity  is 
increased  except  at  the  lowest  concentration  used.  In  the  case  of  mala- 
chite-ammonium carbonate  we  have  the  toxicity  of  soluble  copper  in- 
creased at  the  highest  concentration  (0.287  per  cent  copper)  not  changed 
at  0.143  per  cent  copper  and  0.035  per  cent  copper  and  reduced  at  0.071 
per  cent  copper. 

Finally  in  the  case  of  the  bean  we  find  that  the  presence  of  ammonia 
has  in  all  cases  reduced  the  toxicity  of  soluble  copper. 

The  evidence  is  therefore  in  favor  of  the  view  that  the  presence  of  am- 
monia isL  beneficial  and  not  injurious  as  too  commonly  supposed  though 
it  should  be  noted  that  while  this  beneficent  action  of  ammonia  is  suffi- 
ciently general  to  be  considered  established  and  is  independent  of  the 
rate  at  which  the  cuprammoniums  decompose,  the  data  nevertheless 
clearly  show  that  cuprammonium  sulphate,  the  most  unstable  of  the 
washes,  is  also,  all  things  considered,  less  inj\u*ious  than  cuprammonium 
hydrate  and  carbonates  which  are  very  stable.  Soluble  copper  must 
therefore  be  the  major  cause  of  the  toxicity  of  the  cuprammoniums  in 
the  interim  between  application  and  desiccation. 

B.  Effect  of  the  cuprammoniums  after  they  have  dried  upon  the  plant  and 

are  subject  to  the  action  of  the  weather 

After  the  cuprammoniums  have  dried  upon  the  plant  there  will  be 
present  on  the  leaf  only  a  copper  carbonate  or  hydrate  in  the  case  of  the 
washes  prepared  from  malachite,  but  in  the  case  of  those  prepared  with 
cupric  sulphate  (copper  sulphate  and  ammonia  wash,  Johnson's  mixture) 
ammonium  sulphate  not  in  excess  of  one-half  of  the  cupric  sulphate 
employed  will  also  be  present,  and  in  the  case  of  the  washes  prepared 
from  Burgundy  mixture  we  will  have  besides  the  copper  salt  both  sodium 
bicarbonate  and  sodiiun  sulphate  present,  the  former  to  the  extent  of 
0.41  gram  for  every  gram  of  cupric  sulphate  taken,  the  latter  to  the  ex- 
tent of  0.56  gram  for  every  gram  of  cupric  sulphate  used.^^  In  two 
instances,  therefore,  the  dissolution  of  the  copper  in  meteoric  waters  is 
not  affected  by  the  presence  of  a  foreign  substance,  in  two  instances  the 
foreign  substances  (sodium  sulphate  and  bicarbonate)  are  neither  toxic 

**  The  calculations  are  based  on  the  formula  (vide  Bedford,  Duke  of,  and  Pick- 
ering, S.  U.  loc.  cit.,  p.  86).  5  CUSO4  5  H2O+8  NajCO,.  +  10  HjO  =  2  CuCO,,  3 
Cu(OH),-f  6  NaHCO,-f  5  NajSO*  +  105  H,0. 


268  Phytopathology  [Vol.  7 

at  the  strengths  at  which  they  are  found  in  the  washes  or  solvents  of  the 
copper  salt,  and  in  two  instances  the  action  of  meteoric  waters  is  heightened 
by  the  presence  of  ammonium  sulphate  which  is  a  solvent  of  inflolul>le 
copper  salts  but  non-toxic  itself  at  the  strength  at  which  it  occurs  in  the 
washes.  It  is,  therefore,  clear  that  the  toxicity  of  the  cuprammonium 
washes  after  they  have  dried  upon  the  leaf  can  only  be  due  to  the  prei^- 
ence  of  soluble  copper.  Whence  it  will  only  be  necessary,  in  order  to 
determine  the  magnitude  of  this  toxicity,  to  ascertain  the  dogrec  of 
solubility  of  the  copper  in  the  several  cuprammoniums  as  compared  with 
that  of  a  soluble  copper  salt,  and,  as  already  indicated,  cupric  sulphate 
is  the  only  conunon  inorganic  salt  of  copper  that  satisfies  the  condition!<i 
under  the  experimental  methods  employed.  It  is  desirable  in  teeing 
the  relative  solubility  of  cupric  sulphate  and  of  the  copper  salt  of  the 
dried  cuprammoniums  that  an  organism  sensitive  to  soluble  copper  be 
employed  as  indicator.  The  conidia  of  Plasmopara  viiicola  are,  as  \» 
well  known,  extremely  sensitive  to  soluble  copper*'  and  are  admirably 
adapted  to  thin  purpose  and  were  employed  in  obtaining  the  data  presented 
in  table  2().  The  data  were  obtained  by  spraying  microscopic  slides  dSUsr 
the  manner  tlcscrilN'd  by  Ke<ldick  and  Wallace''  with  the  solutions  to  be 
testeil,  allowing  them  to  dr>'  spontaneously  at  room  temperature  and 
putting  in  Her\'ice  not  earlier  than  twenty-four  hours  after  the  fungicides 
had  dricMl.  In  making  a  test  the  spores  were  washcni  with  distilled  water 
into  a  l)eaker  from  leavers  just  freshly  gathcre<l.  Small  drops  of  water 
with  spores  in  sa^^pt^nsion  were  taken  from  the  l)eaker,  and  place<i  on  the 
slides  which  were  then  incubatiHl  at  or  near  the  optimum  temperature 
for  iiidirei*t  geniiination.'^  Simultaneouf^Iy  a  witness  was  always  pre- 
pare<i  so  that  the  vitiility  of  the  spores  could  lx»  properly  judged  and  no 
exiM^riment  was  considere<l  in  which  the  germination  in  the  witness  prove<i 
low.  Finally  it  should  l>e  noted  that  the  data  given  in  table  20  are  the 
mean  of  five  ex|M*riments  except  in  the  case  of  the  malachite-ammonia 
wjish  with  which  only  two  testn  wore  made. 

Tlu;  d:ita  show  that  the  presence  of  anunonium  sulphate  increases  the 
toxicity  of  a  wiu^h.  the  unit  copper  in  copfXT  sulphate  and  ammonium 
carlM)i)ate  U^ing  mon;  toxic  than  the  unit  coppcT  in  malachito-ammonium 

^  .MillnrtJrt,  .\.  niid  (iiiyon,  l'.  Traitniifnt  du  mildiou  par  Ic  m^lAnge  dr  vulfAtr 
d<»  niivrr  <»t  dt»  rhnux.     Jourii.  agr.  prut.  2:  7<X».     1SS.5. 

Wtithrirh.  K.  IVUt  die  KinwirkiinK  von  MotnllHaltcn  und  Siuren  auf  die 
KtMinfahigki'it  der  Sixtrrn  einifcrr  don  ViTbrritetiitcn  pjiraiiitiirhcn  Filw  unarrer 
Kultun>flnn£4>n.     //<*it.  rnaiiienkr.  2:  ir>-:U.  Hl-IM.     l.Hirj. 

"  Hrddirk.  I>.  and  Wulinn*.  K.  On  a  InUiratory  method  of  drtermtninK  the 
funKit'idal  valui*  t»f  a  ^pr:ly  niixturr  or  nolution.     S<'ienre  n.  s.  SI:  798.     1910. 

**  MflliiiH.  I.  K.  (ii'nninatinn  and  infrctinn  with  the  funguf  of  the  latr  blifcfat 
of  p«>tato.     WiHconmn  Agr.  Kxp.  Sta.  Tech.  liul.  S7:  'M\.     ltU5. 


1917] 


Butler:  Thb  Cuprammonium  Washes 


259 


carbonate.  It  will  be  also  noticed  that  the  highest  toxic  value  for  the 
unit  copper  occurs  in  the  copper  sulphate-ammonia  wash,  though  on 
account  of  the  presence  of  ammoniimi  sulphate  it  is  impossible  to  tell 
to  what  extent  this  high  value  is  due  to  the  presence  of  this  solvent, 
to  what  -extent  to  the  basic  cupric  sulphate.  Judging  from  the  increased 
toxicity  of  cupric  carbonate  in  the  presence  of  ammoniiun  sulphate  it 
would  seem  that  the  high  toxic  value  of  the  unit  copper  in  basic  cupric 
sulphate  is  due  to  the  presence  of  ammonium  sulphate.  However  this 
may  be,  the  table  shows  conclusively  that  the  unit  copper  in  the  cupram- 
monium carbonate  washes  has  a  lower  toxic  value  than  in  a  cuprammonimn 

hydrate  or  sulphate"  wash. 

TABLE  ao 

Relative  toxicity  of  the  cuprammonium  washes  and  cupric  sulphcUe  to  the  spores  oj 

Plasmopara  viticola 


rUirOICIDB  USED 


Malachite-ammonia 

Malachite-ammonium  carbonate 

Copper  sulphate-ammonia 

Copper  sulphate-ammonium  carbonate 
Cupric  sulphate 


LETHAL  STRENGTH 


per  cent  Cu 

0.0033 
0.0057 
0.0027 
0.0035 
0.0019 


SOLUBILITT  or 
COPPER 


Relative  nutnbera 

58.13 
33.33 
70.42 
54.34 
100.00 


Knowing  the  toxicity  of  cupric  sulphate  to  any  given  higher  plant 
it  may  be  calculated  readily  from  the  data  given  in  table  21  at  what 
strength  the  cupranmioniums  would  have  to  be  used  in  order  to  prove 
uninjurious  after  they  had  dried  on  the  fbliage  and  are  wetted  by  meteoric 
water.  Taking  the  plants  used  in  the  experiments  with  cupric  sulphate' • 
we  arrive  at  the  results  shown  in  table  21,  the  data  for  the  cupric  sul- 
phate being  obtained  from  table  15,  either  directly  or  by  extrapolation. 

The  data  presented  in  the  table  show  the  strength  at  which  the  several 
cuprammonimns  could  be  applied  to  foliage  without  producing  injury 
after  diying  due  to  dissolution  of  the  copper  in  meteoric  waters.  The 
question  that  we  must  now  consider  is  whether  these  strengths  are  supe- 
rior to  or  smaller  than  those  at  which  injury  occurs  between  time  of 
application  and  time  of  drying.  If  inferior  then  the  maximum  strength 
at  which  the  cuprammonimns  can  be  used  will  be  governed  by  the  sol- 
ubility of  the  copper  after  drying;  if  superior,  then  the  degree  of  injury 

•*  There  is  no  reason  for  supposing  that  modified  eau  c61este  or  Burgundy  mix- 
ture-ammonium carbonate  would  possess  a  toxicity  materially  different  from  their 
prototypes  mentioned  in  the  table. 

»  See  p.  251. 


260 


Phytopathology 


[Vol.  7 


produretl  while  dr>nng  will  limit  the  strength  at  which  theme  funfdcidcs 
niay  be  useil  safely.  The  data  presented  in  table  22  will  permit  us  to 
answer  the  question  raised. 

The  data  show  that  in  the  case  of  all  four  fuiigicides  the  degree  of  tol- 
eran(*e  of  the  drie<l  fungicides  must  limit  the  strength  at  which  thc>'  cao 
be  aseil. 

TABLK  21 
Calculated  tolerance  of  jAatitn  to  dried  cupramfnoniumn 


ri.JiXT   CMPU>TED 


j     crPMic 
nrLPHATC 

UHIED 

MUJWLT 

M)N-TOXir 


MAXIMTM   STRCNOTH    AT   WHICH  rrraAlllt«>Vtt  Hi 
COt'LO   BB   IHBD 


I 

Malarhite-  ' 
nmniunia 


Malachitt«- 
aninioniuni 
carlx>iiat«'   i 


C'«»pprr 
Hil|»h»l«>- 
ammonia 


•ulpnal*^ 
ainn>««n«uM 
rartmojai* 


CflllMlS 

T(»iiiat<) 

CaiiliflowiT 

PrlarKoniuni 

OxaliM  .    . 


prr  cent  Cu  p*r  r^nt  Cu 

I     0  (K)?.")  0  0110 

[   0  (M)?.')  0  (HID 

0  (NN)7  0  (N)12() 

0  (KM  7  0  ().>».■) 

0  OOP.)  !  0  (KXTJ 

0  0070  i)  ()\:i'}S 


fur  ernt  f^u 

0  (n?2.*> 

0  02-r) 

0  (xrji 

0  int'ii 

0  (K):i7 

0  (n.>:{7 


\ptr  rent  Cu 

-  0  oKm 

I  0  01<N> 
:  0  (XNr.lO 

0  (urio 

;  0  00-3) 
i  0  0112 


Mr  rr<»f  *'% 
0   OI.'iH 

o  oi:{H 

0  IHMJH 

o  a\\:i 
0  miM 
o  oi4:> 


TABI.i:  22 
Affiouut  of  cop  lie  r  toUratrd  in  thr  Atr*Tol  ruprammoni  urns  during  and  after  drv^t^g 


(  OLM  n 


TDMATO 


•  ft«^ 


rcNdu mr.  i  ii>.d 


(%>p{)«*r  tokratril      j     (\>p|irr  |o|rratr«l      i     ('4*|>prr  to|rrat«»l 


Dunne 
dryins 


4ir>ib< 


'    jtrr  rrut        jt^r  frnt    ■    per  rent    •    ptt  rrnl 
Cu  ru  Cu  Cu 


.\!al:irhit<'-aiiiiiionia 


r  rrnt 
Cu 


,  0  01>«W      0  Oi:i.">.S:  0  IKTJ7  ■  0  Ol.'USi  0  02S7      O  <«t<J 


.Malarhitr-aiiitnoiiiiiiii    rarlM>ri-; 


at(* 


'  0  o:{7:i    0  02:17  '  o  ojs7  '  o  oxiT  \  o  oim3    n  tiii:»7 


(*i>p|>4-r  Miilphatc-ainnionia. 


0  inr.N  •  0  0112  '  0  ofki.')  i  o  0112  1  0  01.'>2  1  0  oirjn 


C'np|MT      ^ulI>hatf*-aIllInolliuI^  '  I  I 

rarlMiiiatf  i  0  02.Vt      0  OU.'i      0  OtWio 


I  I 

0  0145  :  O  (r2*>     U  UUI 


(\   Injurtj  hij  niiihtivr  cfftct 

A.*«  wr  \\:\\'r  h*4*ii  th('  ru|>r:iiiiinoiuuiiis  may  pnMluce  injur>'  cluniig 
ilryiiiju  ami  aftrr  drying  dur  to  di>M)hition  of  the  cMipper  in  nwtoorio 
^:it«T>.  Whni  tin*  injuria  pro<lur<Ml  l)y  thrs4»  sourw^s  is  sufficiently 
distant,  thrir  mutual  rfTrrt>  rnnaiii  diMiiirt,  but  when  thev  wcur  ncarlv 
^inlultaIl('4>tl^ly  an  injury  gn^atrr  than  that  <lut»  to  the  sum  of  the  eflft-rt* 


1917] 


Butler:  The  Cuprammonium  Washes 


261 


of  the  injury  produced  during  drying  and  after  drying  is  to  be  anticipated 
since  as  SchandeH^  and  Barker  and  Gimingham^^  have  pointed  out 
soluble  copper  is  more  injurious  to  recently  than  to  remotely  injured 
leaves.  The  data  presented  in  table  22  show  clearly  that  if  injury  is 
produced  during  diying,  injury  will  also  follow  wetting  with  meteoric 
water.  The  converse  is  not,  however,  necessarily  true,  since  the  rate 
of  drying  markedly  affects,  as  we  have  seen,  the  degree  of  tolerance  of 
copper. 

III.    PRACTICAL   considerations 

If  we  consider  the  strength  at  which  the  cuprammoniums  sffe  or  have 
been  used  in  practice,  we  will  find  that  these  fimgicides  are,  or  have  been, 
as  will  be  seen  from  table  23,  applied  at  a  strength  in  copper  ranging 
from  7.2  to  47  times  the  lethal  concentration  for  Plasmopara  viticola, 

table  23 

Strength  at  which  the  cuprammoniums  have  been  most  commonly  employed  in  practice 
and  lethal  concentration  of  the  same  for  Plasmopara  viticola 


a 

B 

A 

PUNOICIDE   USED 

Strength  at 
which  applied 

Lethal 
concentration 

RATIO    = 

\lalachitc-aininonia 

per  cent  Cu 

0 . 0493 
0.0264 
0 . 0270 
0  0254 

per  cent  Cu 

0.0033 
0.0057 
0.0027 
0.0035 

1: 14.9 

Malachite-ammonium  carbonate 

CoDDer  sulohate-ammonia 

1:4.63 
1:47.03 

Copper  sulphate-ammonium  carbonate 

1:7.25 

Now  since  the  cuprammoniums  may  all  be  considered  equally  adhesive, 
as  regards  resistance  to  mechanical  shock,  because  they  form  precipitates 
composed  of  particles  of  nearly  like  size,  the  concentration  at  which  they 
are  applied  should  bear  a  definite  relation  either  to  their  efficiency  or 
efifectiveness.'*  But  an  inspection  of  table  23  will  immediately  show  that 
no  relation  exists  between  lethal  concentration  and  strength  of  applica- 
tion whether  we  take  as  our  criterion  efficiency  or  effectiveness.     The 

"  Schander,  R.  Uber  die  physiologische  Wirkung  der  Kupfervitriol  Kalkbriihe. 
Landw.  Jahrb.  33:  — .     1904. 

••  Barker,  B.  T.  P.  and  Gimingham,  C.  T.  The  action  of  Bordeaux  mixture  on 
plants.    Ann.  Appl.  Biology  1:  II  et  seq.     1914. 

*•  The  efficiency  of  a  fungicide  depends  both  on  the  solubility  of  the  copper  and 
its  toxicity  when  in  solution.  Usually,  though  not  necessarily  always,  solubility 
is  a  measure  of  toxicity  and  conversely.  Effectiveness  depends  on  the  power  of  a 
fungicide  to  withstand  weathering,  that  is,  to  possess  adhesive  properties,  while 
at  the  same  time  yielding  sufficient  soluble  copper  to  give  protection  from  a  specific 
organism  or  organisms. 


262 


Phytopathology 


(Vol.  7 


formulae  in  use  should  therefore  be  amended  so  as  to  give  a  numerical 
relation  between  lethal  concentration  an<l  strength  of  application. 

liCt  UH  first  of  all  determine  the  factor  required  to  give  maximum 
effectiveness. 

Since  we  have  been  unable  to  assign  a  value  to  this  factor  frr>m  the 
data  presented  in  table  24,  it  will  be  necessary  for  us  to  determine  it  in- 
directly  and  this  we  can  do  from  our  knowledge  of  Bordeaux  mixture. 
Acconling  to  a  recent  French  enquiry***  a  2  per  cent  Bordeaux  mixture  is 
ncccssar>'  to  give  adequate  protection  from  Phmnopara  viticola  in  yca» 
favorable  to  the  development  of  this  parasite  though  in  years  when  in- 
festation is  not  severe  1  per  cent  mixtures  meet  more  or  less  satisfactorily 
the  re<|uircmcnts  of  practice.  In  the  United  States,  on  the  other  hand, 
both  Plasmopara  viticola  and  Phytophthora  infeatans  may  be  .satisfac- 
torily held  in  check  by  1  per  cent  Bortleaux  mixtures  though  1.2o  per 
cent  mixtures  are  ako  commonly  emplc)y<Hl.  We  may  therefore  in  all 
propriety  take  a  1  per  cent  Bordeaux  mixture  for  our  standanl  of 
comparison. 

Now  Bordeaux  mixture  1:  1  is  toxic  to  Ixjth  Plasmopara  viticola  and 
Phytophthora  infiHtans*^  at  0.0039  per  cent  copper  which  gives  us  a  factor  of 
64  as  the  re<juir(»ment  of  practict^  for  adcKiuaU^  protection.  Accepting  this 
factor  of  M  for  Bonicaux  mixture  the  factors  necessary  to  apply  to  the 
cupramnumiums,  due  regard  Innng  taken  of  the  n^lative  (efficiency  of  the 
unit  coppcT,  in  ordiT  to  obtain  satisfactory'  pn)tection  would  then  be  as 
indicato<i  in  table  24. 

TABI.K  21 
Fariarn  by  which  the  lethal  nmrtntnitiorm  oj  the  aereral  cufframmoniumM  mu*!  he  mui- 

tipliiii  in  onier  to  obtain  adequatt   ftrotertion 


rt-KUk'iDC  rtiKD 


UCTNAL 
COMt  KWTIIATIOM 


lionli'AUx  uiixtun*  1:1 

Miilnrhitr-iiinniunia 

Mnlarhit4*-Hiiiiii«)iiiuiii  rarU«imtr 

( *t>p|M*r  Milphiitc-iiiiiiiiotiiti 

C'oplMT  Milphatc'-aiiiiiuiiiiiiiii  rnrlNiiiatt' 


0  n(»9 

0  (X»33 

0  ortt7 

0  0027 
0  0035 


r4rToa 


64 
53  7 
93  4 
44  I 

56  9 


Fntiii  th«'  ilata  giv(*n  in  table  24  one  (*an  n^adily  d(*teniune  the  stn*ngth 
at  uhirh  the  riipraiiunoniuiiis  hhould  Im*  us<*<1  in  pradice  in  order  to  ul>> 
tiiiii  :i  pnae<'tion  ^*ul^^<tanti^llly  (H{uivalent  to  that  given  by  Bonicaux 
iiiivtun'.  :tn<i  when  the  data  m»  obt^iined  :u'e  eoiiipanNl  i^nth  the  strengths 

*   (':ipiiM.  J.     Ia'a  traitiMiieiitH  ilu  iiuMiou.     Urv.  d<*  vit.  44:302.     1916. 
•'  WiM-niiHin  Agr.  i:xp.  Sta.    IVch.  Hul.  37:  M).     1915. 


1917] 


Butler:  The  Cuprammonitjm  Washes 


263 


employed  in  practice,  as  in  the  following  table,  we  find  that  the  calcu- 
lated strengths  are  from  fom*  to  twenty  times  greater  than  those  that 
have  been  actually  used  except  in  the  case  of  the  copper  sulphate  and 
ammonia  wash  when  the  agreement  is  close.  But  since  the  cuprammo- 
niums  have  not  afforded,  at  the  strengths  used  in  practice,  protection 
commensurate  with  Bordeaux  mixture  and  we  are  now  in  a  position  to 
understand  why  they  have  not,  the  formulae  employed  should  be  emended 
so  as  to  approach  the  calculated  values  indicated.  But  the  actual 
strengths  employed  will  be  determined  by  the  tolerance  of  the  plant 
sprayed  to  the  fungicide  in  the  interim  between  appUcation  and  desicca- 
tion, and  to  the  solubiUty  of  the  dried  wash  in  meteoric  waters.  We  will 
first  of  all,  consider  the  latter  case. 

The  dried  cupranunoniums  must  not,  of  course,  yield  on  being  wetted 
more  soluble  copper  than^the  sprayed  plant  will  stand.    Let  us  accept 


table  25 


Strengths  at  which  the  cuprammoniums  are  used  in  practice  and  strengths  at  which 
they  should  he  employed  in  order  to  give  protection  equivalent  to  Bordeaux  mixture 


rUNOlCTDK  USED 

BTRENQTH  USED 
IN  PRACTICE 

STRENOTH     EQUIVA- 
LENT TO    1  PER 
CENT  BORDEAUX 
MIXTURE 

Malachite-ammonia 

per  cent  Cu 

0.0493 
0.0264 
0.1270 
0.0254 

per  cent  Cu 
0.1772 

Malachite-ammonium  carbonate 

0.5323 

Copper  sulphate-ammonia 

0.1190 

Copper  sulphate-ammonium  carbonate 

0.1991 

for  the  sake  of  concreteness,  the  value  for  the  tomato  0.0075  per  cent 
copper.  This  percentage  of  metallic  copper  is  yielded  by  a  0.045  per 
cent  copper  sulphate  and  ammonia  wash  under  laboratory  conditions 
but  the  tolerance  of  the  tomato  under  field  conditions  may  be  safely 
placed  at  0.125  per  cent,  since  rains  even  of  moderate  intensity  will  carry 
away  appreciable  amoimts  of  the  fungicide.  And  since  in  the  other 
cuprammoniums,  as  we  have  seen,  the  copper  is  less  soluble  than  in  the 
copper  sulphate  and  ammonia  wash,  we  may  safely  use  them  at  the 
same  relative  concentration  which  would  then  give  us  the  following  as  the 
permissible  strengths  at  which  they  can  be  applied  without  injury  from 
soluble  copper  resulting  to  a  plant  tolerating  0.0075  per  cent  soluble 
copper.  As  will  appear  from  a  consideration  of  table  26,  the  calculated 
values  for  soluble  copper  tolerated  are  lower  than  those  obtaining  in 
practice  for  the  malachite-anamonia  and  copper  sulphate-ammonia  washes 
and  higher  in  the  case  of  the  two  cuprammonium  carbonate  washes. 


2G4 


Phytopathology 


[Vol.  7 


The  (lata  presented  in  table  26  further  show  that  it  is  impotwible  to 
apply  the  ouprainnioniums  at  strenjijth*s  equivalent  in  effectivencsw  to  1 
per  cent  Bordeaux  mixture  when  the  plants  spraytni  will  not  tolerate  niorp 
than  0.(K)75  per  cent  soluble  copper  since  in  onler  to  obtain  equivalence 
the  plant  sprayed  would  have  to  tolerate  0.0158  per  cent  soluble  coppiT. 

We  have  adniitteil  that,  under  the  conditions  of  practice  plants  will 
tolerate  cupraninioniunis  2.8  times  stronger  than  tolerated  under  critical 
conditions.  It  remains  now  to  be  seen  whether  cuprammoniumA  <»f  this 
strenjrth  can  l)e  applied  without  injury  resulting  during  dr>nng.  The 
data  present(Hl  in  table  27  show  that  in  the  cjise  of  the  tomato  uxi<ler 
the  conditions  of  quick  drying,  all  the  cupranunoniums  except  tlic  mala- 
chitt^junmonia  wa.^h  can  Ix*  us(»d  at  tiie  nH|uired  concentration,  hut  that 
under  the  conditions  of  slow  drying  inalachite-ammonia  and  malachite- 
anunonium  carbonate,  the  latter  particularly,*  are  toxic  at  a  lower  con- 
centration than  that  deinaii(lcd.     In  tlu^  case  of  the  Coleus  we  find  <|uick 

TAIU.K  2« 

Strt'figthM  at  which  tht  rupramtruniiumM  may  be  UKcd  withoui  an  iujurinu^  ntHi»uftt  •»/ 
mtluhlr  rop/HT  forming  on  wetting  with  meteoric  water,  a  plant  rrnixtant  Itt  ft  mfTS 
f}er  cent  foluhle  eop/nr  in  ing  presupjHtsed 


r\  sou  tut.  \  nr.n 


•»TH»  N«.TH 
TOM  M«T>  II 


•TRrN««TN    '  ••  t* 


Nf.'iiarliitf'-HininnTii:! 

Mal:ir|iitc-;tnifii<iiiinin  ('Hr)N)iiat«' 

( *op|MT  »>ul|>h:it4'-aiiiiii<»ni}i 

i^opfMT  huiphati'-aiiiiiioiiiiiin  <*:ir)M>ti:it<* 


/Mr    rrnt  f'u 

0  (WIT 

0  mio 


I 


(»  ova 

0  O.Y>l 


drying  jH-nuits  the  us4'  in  evrry  rast'  (»f  MrongcT  s^ilutions  than  tolenifnl 
in  the  driisl  wa.*<h,  whil<»  tlio  n»vrrs<»  is  the  vh-a*  if  .slow  dr>'ing  is  p4*nnitte«l. 
In  the  ca»*  <»f  the  Imviu  tin*  plant  will  tolerate'  Wronger  dr>'ing  than  dri«tl 
w:i.»*Im»s.  In  tho  ras4»  of  thr  tomato  and  ( 'oleus  the  wjislM-s  cjin  all  lie  u?«*«i 
at  11.7  tiinrs  their  toxi<'  <'on<M»nt ration  to  Plasmoimra  vHicvia  when  «lri«*«l 
(|uirkly  but  in  tlir  ra>4' of  the  iH'an  thry  can  In*  appli<'<l  at  only  3.^i  tim«-!« 
tln'ir  K'thal  «*onrrnt ration  with  safi^ty,  no  matter  how  .*ilowly  or  c|uirkly 
th«'  w:ls|m's  are  driiMJ.  It  siM-ins,  thrn»f<»n»,  <'lrar  that  the  cuprainmoniunu* 
can  n«»t  Ik»  ron.Md«*nNl  a,<  efT«»rtive  as  Hordraux  mixtun*  for  the  ctmtnJ 
of  pani'^itir  organisiiLs  whirh  «io  not  n^juin'  a  <*onct»ntnition  in  S4»lublo 
cop|M*r  gn\atcr  tlian  that  yi<»ldc.d  by  the  latter.  We  have  now  t«i  C'»n- 
hidiT  thf  cupraminoniums  fn»in  the  |M»int  of  view  of  efficiency. 

TIm'  unit  ropjxT  in  the  (*upramm<M)iunLs  has  generally  IwH'n  con.sidiTetl 
iiion*  rtficicnt  than  the  unit  ropfxT  in  Hord<'aux  mixtun*.  and  this  opinion 
\^  mhloubt<H||y  well  grounded  wh«*n  thr  cuprammoniunts  which  an*  \\t:¥> 
ti<*all\'  neutral  as  scMin  as  dry  an*  (M^mpan^d  with  alkaline  l^mleaux  mix- 


1917] 


Butler:  The  CuPRABfMONiUM  Washes 


265 


tures  in  which  the  copper  is  without  action  during  the  time  required  to 
reach  neutrality;  but  when  compared  with  neutralized  or  neutral  Bor- 
deaux mixture  at  the  lethal  strengths  to  Plasmapara  viticola  the  difference 
in  favor  of  the  cuprammoniums  is  indeed  small.  In  the  most  efficient 
wash  (copper  sulphate  and  ammonia)  the  unit  copper  has  a  value  only 
1.44  times  that  of  Bordeaux  mixture  and  in  the  least  efficient  (malachite- 
ammonium  carbonate)  it  is  1.46  times  less  active.  But  in  fimgi  resistant 
to  copper  the  unit  copper  in  the  cuprammoniums  may  be  manifold  that 
of  Bordeaux  mixture,  the  highest  values  being  given  by  the  copper  sul- 
phate and  ammonia  wash.  For  instance  in  the  case  of  the  uredospores 
of  Puccinia  Antirrhini  the  efficiency  of  the  unit  copper  in  the  copper 
sulphate-ammonia  wash  is  very  much  greater  not  to  say  infinitely  greater 
than  the  unit  copper  in  Bordeaux  mixture  since  it  would  appear  that  the 
latter  is  non  toxic  at  all  concentrations.^^ 

TABLE  27 

Amount  of  copper  tolerated  in  the  cuprammonium  washes  during  drying  by  the  tomatot 

Coleus  and  bean 


TOMATO 

COLBUS 

BBAN 

rUNQlCIOB  USBD 

strencth  of  dried 
wagb  tolerated 

StreoKth 
tolerated 

Strencth  of  dried 
wash  tolerated 

Strength 
tolerated 

Strencth  of  dried 
wash  tolerated 

Strength 
tolerated 

Wash  dried 
quickly 

Wash  dried 
slowly 

Wash  dried 
.  quickly 

Wash  dried 
slowly 

Wash  dried 
quickly 

Wash  dried 
slowly 

Malachite-ammonia. . . . 
Malachite-ammonium 
carbonate 

per  e^nt 
Cu 

0.0386 
0.0668 
0.0317 
0.0410 

per  cent 
Cu 

0.0359 
0.1437 
0.0635 
0.127 

per  cent 
Cu 

0.0327 
0.0287 
0.0635 
0.0635 

per  cent 
Cu 

0.0386 

0.0668 
0.0317 
0.0410 

per  cent 
Cu 

0.0718 

0.1437 
0.0635 
0.0635 

per  cent 
Cu 

0.0298 

0.0315 
0.0228 
0.0254 

per  cent 
Cu 

0.0089 
0.0154 
0.0073 
0.0101 

per  cent 
Cu 

0.0301 
0.0229 
0.0203 
0.0279 

per  cent 
Cu 

0.0287 
0  0183 

Copper   sulphate-am- 
monia  

0.0152 

Copper    sulphate-am- 
monium carbonate. . . 

0.0228 

It  is  therefore  clear  that  in  the  control  of  parasitic  endophytes  the 
spores  of  which  are  highly  resistant  to  soluble  copper,  the  cuprammoniums 
may  be  of  very  considerable  value  provided  the  plant  to  be  sprayed  will 
withstand  the  concentration  demanded.  But  except  in  those  cases  where 
Bordeaux  mixture  is  non  toxic  to  the  parasite  from  which  protection  is 
sou|2:ht  it  does  not  seem  to  me  that  the  cuprammoniums  as  a  class  or  any 
one  cuprammonimn  in  particular  possess  merits  sufficient  to  warrant 

**  Doran^  W.  L.  Controlling  snapdragon  rust.  Value  of  copper  and  sulphur. 
Florists'  Exchange  48:  501.    1917. 


266  Phttopatholoot  [Vol.  7 

their  emfdoyment  in  practice,  especially  ainoe  the  quality  of  inconspio* 
uouaneeB  can  be  obtained  quite  readily  with  Bordeaux  mixtures  1 :  alkalinity 
Bordeaux  mixture  1 :  alkalinity  is  no  more  conspicuous  than  the  copper 
sulphate  and  ammonia  wash  when  the  same  amount  of  copper  is  applied 
per  square  meter  in  both  cases  but  since  the  latter  usually  wets  the  foliage 
better  than  the  former  it  appears  to  be  less  highly  colored,  due  to  the 
fact  that  the  copper  is  spread  over  a  larger  surface.  Whenever  Bordeaux 
mixture  1 :  alkalinity  does  not  wet  the  foliage  sufficiently  to  offer  the  proper 
degree  of  inconspicuousness,  the  wetting  power  oi  the  mixture  may  be 
increased  by  the  addition  of  an  infusion  of  quillaia  (i.e.,  saponin)  or  a 
small  amount  of  casein.  It  is  therefore  not  necessary  to  resort  to  a  cupram- 
monium  when  an  inconspicuous  copper  fungicide  is  required. 


SUMMABT 

1.  The  cuprammoniums  met  with  in  practice  belong  chemically  in 
one  or  the  other  of  the  following  groups:  (1)  cuprainmonium  sulphate; 
(2)  cuprammoniuni  hydrate,  and  (3)  cupraninumium  carbonate. 

2.  When  decomposed  by  drying  cupranunonium  sulphate  deposits 
the  copper  as  a  basic  sulphate,  cuprammonium  hydrate  yieldB  a  copper 
hydrate,  and  cuprammonium  carbonate  a  copper  carbonate. 

3.  (^uprammonium  sulphate  is  very  unstable;  cuprammonium  hydrate 
and  carl)onatc  very  stable. 

4.  The  cuprammoniums  are  more  toxic  when  slowly  than  when  quickly 
dried. 

5.  The  toxicity  of  the  cuprammoniums  during  drying  and  on  weather- 
ing is  due  to  soluble  copper. 

6.  The  copper  sulphate  and  ammonia  wash  and  Johnson's  mixture  are 
less  injurious  than  the  malachite  washes. 

7.  The  cuprammonium  washes  arc  more  efficient  and  effective  than 
Bordeaux  mixture  when  large  amounts  of  soluble  copper  arc  required  to 
give  pn>tcction. 

8.  The  cuprammonium  washes  arc  less  effective  than  Bordeaux  mix- 
ture when  hmall  amounts  of  soluble  copper  suffice  to  give  protecticin  hut 
with  the  exception  of  the  mala(*hite-ammonium  carbonate  wasli  are 
slightly  more  efficient. 

9.  The  relative  efficiency  of  the  unit  copper  in  the  cuprammoniums  is 
in  decreasing  onier  as  follom-s:  Copper  sulphate-ammonia,  malachite* 
aiiunonia.  copper  sulphute-ainmonium  curlxinate,  malachite-ammonium 
carbonate. 

10.  Tlie  cuprammoniums  nmy  be  used  at  11.7  times  their  lethal  con* 


1917]  Butler:  The  Cxtprammonium  Washes  267 

centration  for  Plasmopara  viticola  on  plants  not  affected  by  0.0075  per 
cent  soluble  copper. 

11.  The  cuprammoniums  are  of  limited  practical  applicability  and 
should  not  be  used' in  lieu  of  Bordeaux  mixture  whenever  the  latter  yields 
sufficient  soluble  copper  to  give  protection. 

New  Hampshire  Agricultural  Experiment  Station 
Durham,  New  Hampshire 

BIBLIOGRAPHY 

AuDOTNAUD.    Le  mildiou  et  les  composes  cupriques.    Prog.  agr.  et  vit.    1885. 
Bedford,  Duke  of,  and  Pickering,  S.  U.    Woburn  Experimental  Fruit  Farm 

Report,  11:  1-1429.    1910. 
BouRCART,  E.    Les  maladies  des  plantes,  372-382.    1910. 
Chester,  F.  D.    The  copper  fungicides,  Joum.  Myc.  6:  22-24.    1891. 
Gastine,  G.    Emploi  du  carbonate  ammoniacal  de  cuivre  contre  le  peronospora. 

Prog.  agr.  et  vit.  8:  114^117.    1887. 
HoLLRUNG,   M.    Handbuch   des   chemischen  mittel   gegen   Pflanzenkrankheiten. 

1898. 
Johnson,  S.  W.    Note  by  the  Director.   Connecticut  Agr.  Exp.  Sta.  Rept.  1890: 118. 

1891. 
LoDEMAN,  E.  G.    The  spraying  of  plants.    1899. 
MoissoN,  H.    Traits  de  chimie  Min^rale,  5.    l905. 
Patrigeon,    G.    Nouveaux  proc6d^    de    traitement   du .  mildiou.    Joum.   agr. 

prat.  1:  881-882.    1887. 
Penny,  C.  L.    The  preparation  of  ammoniacal  solution  of  copper  carbonate.    Dela- 
ware Agr.  Exp.  Sta.  Bui.  22.    1893. 
Pickering,  S.  U.    Note  on  an  anmionio-copper  sulphate.    Journ.    Chem.  Soc. 

Trans.  48:  336-339.    1883. 
Pickering,  S.  U.    On  the  basic  sulphates  of  copper.    Chemical  News  47: 182.     1883 


288  Phytopathology  [Vou  7 

DESCRIPTION  OF  PLATES 

Plate  III 

Effect  of  the  malachite-ammonium  carbonate  waah  containing  0.28  per  oeat 
Cu  on  the  tomato  var.  Bonny  best.  Plants  on  the  left  dried  quickly,  planta  on 
the  right  dried  slowly.  Photograph  taken  twenty-four  hours  after  tlie  fungicide 
was  applied. 

Plate  IV 

Kffect  of  the  malachite-ammonia  wash  containing  0.28  per  cent  Cu  on  tlie  lomato 
Tar.  Bonny  l>ost.  Plants  on  the  left  dried  quickly,  plants  on  the  right  dried  tlowlj. 
Photograph  taken  twenty-four  hours  after  wash  was  applied. 

Plate  V 

Tomato  var.  lionny  liest  photographed  twenty-four  hours  after  being  spr»yed 
with  1  per  cent  cuprir  Mulphate.  Plants  on  the  left  dried  quickly,  plants  oo  the 
right  dried  slowly.  The  plants  dnod  quickly  showed  slight  scorching  of  ytning 
leaflets  at  the  time  of  making  thf  photograph  but  the  injury  was  not  sufficiently 
marked  to  show  in  the  plate;  the  plaiitrt  dried  nlowly  were,  on  the  other  hand,  very 
seriously  injurc<l  all  the  leaves  UMng  with(*rt>d  and  flaccid. 

Plate  VI 

Kffect  of  ammonium  hydn>xid  containing  4.11  \H»r  cent  ammonia  on  the  tomato 
Tar.  Bonny  best.  Plants  showing  no  apparent  injury  dried  quickly,  withered  plants 
dried  slowly.     Hiotograph  taken  twrnty-four  hnurs  after  treatment. 

Platk  VII 

Fio.  1.  Kffect  of  ammonium  rarUinate  containing  0.96  per  cent  ammonia  on  the 
Coleus  var.  (iolden  l)edder.  Plant  on  tin*  right  dried  quickly,  plant  on  the  left 
dried  slowly.  The  photograph  wan  taken  furtyHMght  hours  after  the  salt  was 
sprayi*d  on  the  plants. 

Fig    '2.  Kffect  of  a  '2  |mt  c«*nt  Holution  of  aninionium  sulphate  on  the  bean  var 
Dwarf  hortiniltural.     Plant    on   the   left   dried  slowly,   plant  on  the  right  dried 
quickly.     Photograph  taken  forty^Mght  hours  after  treatment. 

Pi.\tk  VIII 

<iraphH  t*ho\%iiiK  the  relative  toxicity  of  f|iiickly  iitid  mIohIv  dri«*<l  solutions  of 
cuprtr  trilph.'ite  to  the  < 'oleiiH.  tiHiiato.  Ox.mIih.  Perl:irKoiiiiiiii.  lM»an  and  cauliflower 

Pl.VM     I\ 

(fr:ipli!«  -tliiiuiriK  rrLitive  toxicity  of  i)iiickly  and  sIohIv  dried  m^hitions  of  amm«>- 
niuiit  li\<lrii\iii  :irid  aniinoriiuiii  carl)on:ite  to  the  )N*:iii  and  cuulitlowrr. 

Pi.\Ti:  \ 

(iraph-  »lif»uiiik;  ril.itive  tn\irir\  nf  i|tiii-kl\  .iihl  •tliiulv  1 1  ned  mil  utii>ns  of  ammo- 
nium h\ilri>\til    titil  :tiiitiioiiiiiiii  i\irlH>ii.iti'  lti  ttio  tnni:it«t  :iitd  <^>Ieus 


rtlYTOPATIIOIXX>Y.  VI t 


FHVTOPATHOIJJGV,  VII 


PUATK  VIII 


HtUOTYM  00.  tOiTO*! 


^ASHKS* 


PHYTOPATHOLOGY,  VII 


PLATB  X 


O.  B.  d«l. 


BuTUER :  Th«  Cuprammonium  Washes 


HtUOTVPt  00.  MtTOM 


1917]  Boncquet:  Bacillus  morulans  271 

from  diseased  plants  or  portions  of  plants,  it  has  not  been  possible  to 
produce  curly  top  by  inoculation  with  cultures  of  this  organism;  that  the 
same  organism  has  been  isolated  from  the  surface  of  beet  seed,  the  sur- 
face of  normal  sugar  beet  leaves  and  from  the  soil  about  the  roots  of 
sugar  beets.  Also  that  certain  bodies  which  seem  to  represent  the  same 
organism  have  been  found  in  great  abimdance  in  curly  top  sugar  beets, 
in  the  interior  of  the  sieve  tubes,  accompanying  a  specific  lesion  in  the 
phloem,  and  that  similar  bodies,  in  varying  but  much  less  abundance,  were 
found  in  the  same  tissue  in  supposedly  normal  beets  or  those  with  various 
morphological  irregularities  of  the  foliage  (fig.  1).  Whatever  may  be  the 
entire  significance  of  the  organism  in  question,  its  peculiarly  abundant 
occurrence  in  connection  with  the  sugar  beet  and  its  apparent  relation  to 
curly  top  have  seemed  to  justify  its  careful  study,  and  it  is  the  piupose  of 
the  present  article  to  describe  more  in  detail  the  characteristics  of  this 
species,  to  which  the  i^une  Bacillus  monUans  has  been  given.''^^-    ..' 

THE   DISEASE 

ft 

The  disease  of  sugar  beets  called  curly  top  is  of  annual  occurrence 
throughout  the  sugar  beet  growing  regions  of  Colorado,  Utah,  Idaho  and 
California.  The  severity  of  the  disease,  however,  varies  greatly  from 
year  to  year.  Some  years  veritable  disasters  are  produced  by  curly  top, 
thousands  of  acres  of  sugar  beets  being  totally  destroyed  after  all  the  ex- 
pense  of  preparing  the  ground  and  planting  the  crop  has  been  imdergone. 

Symptoms  on  leaves 

The  comparative  size  of  the  inner  and  outer  leaves  is  altered.  The  in- 
ner leaves  are  dwarfed,  the  petiole  especially  becoming  shorter  and  flatter 
than  the  normal,  while  the  outer  leaves,  if  already  full  grown  before  the 
disease  becomes  apparent;  maintain  their  natural  size  and  shape  and,  for 
some  time  at  least,  their  color,  although  they  may  finally  turn  yellow 
and  die  prematurely.  The  first  symptom  of  abnormality  plainly  visible  to 
the  eye  is  a  distinct  transparency  of  the  finest  venations  of  the  youngest 
leaves^  This  transparency  starts  at  the  base  of  the  leaf  blade.  Gradu- 
ally the  abnormality  works  higher  on  the  leaf  until  finally  the  whole  leaf 
is  aflfected.  The  youngest  leaves  are  first  to  suffer;  the  older  ones  (such 
as  are  not  already  full  grown)  show  the  symptoms  as  their  expansion  and 
growth  progress.  Almost  simultaneously  with  the  appearance  of  the 
transparency  of  the  veins  small  warty  protuberances  appear  upon  the 
veins  on  the  under  surface  of  the  leaves,  eventually  even  upon  those  which 
are  of  the  smallest  size  visible  to  the  eye  (fig.  2) .  The  margins  of  the  af- 
fected leaves  then  begin  to  curl  slightly  upward  so  as  to  expose  the  lower 


1917]  Boncquet:  Bacillus  morulans  273 

several  abnormal  bendings;  the  angle  of  each  bend  is  slightly  swollen  and 
if  the  rootlet  is  far  advanced  the  swollen  region  appears  to  be  necrotic 
(fig.  3).  When  the  main  root  is  cut  transversely  the  successive  rings  of 
vascular  tissue  appear  discolored.  On  careful  examination  it  will  be 
observed  that  the  phloem  is  the  only  part  of  the  vascular  system  which 
suffers  severely.  This  phloem  discoloration  is  observed  more  or  less 
throughout  the  whole  system  in  the  veins  as  well  as  in  the  roots.  This, 
however,  only  becomes  apparent  to  the  naked  eye  when  the  disease  has 
reached  its  severest  aspect. 

Cause  of  the  disease 

It  was  E.  D.  Ball*  who  discovered  that  the  sting  of  the  insect  EuteUix 
tenella  Baker  is  a  necessary  factor  in  the  causation  of  this  disease.  His 
observations  were  confirmed  by  Shaw,'  and  very  fully  tested  and  confirmed* 
by  Smith  and  Boncquet.  The  latter,  however,  together  with  Hartung,* 
proved  a  fact  which  had  previously  been  suspected,  that  EuteUix  teneUa 
is  not  the  fundamental  factor  in  the  causation  of  this  disease,  but  rather 
must  be  a  carrier  of  a  second  factor,  presumably  a  parasitic  micro-organ* 
ism.  This  discovery  made  very  important  a  thorough  search  for  and  study 
of  all  micro-organisms  which  possibly  could  be  found  in  connection  with 
the  disease,  and  it  is  with  this  portion  of  the  study  of  curly  leaf  that  the 
present  article  hais  to  do. 

BACTERIOLOGICAL  INVESTIGATIONS 

The  methods  and  detailed  results  through  which  the  conclusion  was 
reached  by  the  writer  that  Bacillus  morulans  inhabits  constantly  and 
specifically  plants  affected  with  curly  top,  as  well  as  occurring  in  certain 
other  situations  may  first  be  described.  It  was  decided  at  the  outset  to 
make  a  very  thorough  and  accurate  search  for  any  organism  which  might 
be  present  in  the  tissues  of  plants  affected  with  the  disease.  The  unfav- 
orable or  at  best  imcertain  results  reported  by  previous  investigators 
along  this  line  led  to  the  belief  that  the  problem  would  be  a  diflScult  one, 

*  Ball,  E.  D.  The  beet  leaf  hopper.  Utah  Agr.  Exp.  Sta.  Ann.  Rept.  16:  16. 
1905. 

The  Genus  Eutettix.    Proc.  Davenport  Acad.  Sci.,  12:  41  and  84.     1907. 

The  leaf  hoppers  of  the  sugar  beet  and  their  relation  to  the  "curly  leaf" 

conditions.     U.  S.  Dept.  Agr.  Bur.  Ent.  Bui.  66,  pt.  4.    1909. 

»  Shaw,  H.  B.  The  curly  top  of  beets.  U.  S.  Dept.  Agr.  Bur.  PI.  Ind.  Bui.  181. 
1910. 

*  Boncquet,  P.  A.  and  Hartung,  W.  J.  The  comparative  effect  upon  sugar  beets 
of  Eutettix  tenella  Baker  from  wild  plants  and  from  curly  leaf  beets.  Phytopath» 
h\  348-349.     1915. 


274  Phytopathology  (Vol.  7 

but  at  the  siiine  time  a  Rtudy  of  the  nature  of  the  disease  had  led  to  a  wry 
strong  feeling  that  some  parasitic  micro-organism,  of  which  the*  in.*««*ct 
Eutettix  tenella  was  presumably  a  carrier  or  secondary  host,  muKt  lie  in* 
volveti  in  this  disturbance.  Assuming  then  that  the  sought-for  <>rganL<ni 
would  l)e  an  obscurer  one  and  difficult  to  demonstrate  by  onlinar>'  cuhund 
or  histological  methoils,  various  siXMrial  and  somewhat  elaborate  culture 
methods  were  attempte<l. 

Preparation  of  media 

The  following  meilia  which  seemed  most  promising  fortius  purpoM*  wen* 
preparcMJ: 

FilUrni  hrrt  juicr.  For  thi»  purpom*  thr  plniitH  from  which  the  juic«»  wan  (lf«irnl 
'wcro  wiiHhr<l  nM  thorouKhly  uh  poHsihle  in  Hterilisod  wntor  Aiid  then  icri>un(i  fiiH*  in  i 
ninit  ^rindor.  In  niont  ram^s  1(K)  vv.  of  (liHtillcMi  wntor  wait  a(ldf*<i  to  rarh  1(1)  icmn.t 
of  hcrt  pulp  and  t)i«*  niasH  w»h  thon  covered  and  h*ft  xtandinK  for  two  houri*.  Thr 
rnihhtMl  material  waM  Hii)iHc(]Uently  put  into  clean  ch(H'iM*cloth  and  the  juir«*  Mpifrfrd 
out  in  a  prcHi*.  Thf  juice  thus  o)>tained  wa8  fluhitequently  dilutc^l  twin*  it*  vuluinr 
with  n  (t  Halt  sf>lution.  VariouH  dcf^recM  of  dilution  have  \wvi\  einployni.  hn«ifvrr 
from  th«'  original  juice  up  to  alxnit  ten  t<»  one.  either  in  Rait  aolution  <ir  w.itvr  In 
mime  cas4't<  tlic  solution  was  then  titrated  and  hroURht  to  the  neutral  p<iint  «if  phfn>M- 
phthalein  with  so<lium  hydroxid.  This  juice  was  now  clear,  nliichtly  hmvin  and 
passi'd  easily  thmufch  a  common  filter  pafn'r.  After  it  had  iN'cn  filtered  through 
pafMT  it  wa>  parsed  throuKi)  h  mciliumHh'nse  liiTkefeld  filter  camlle  for  pur|M»<M-»  nf 
sterilization.  An  apparatus  wan  e^perially  devised  for  this  purjMim*.  a  fitriii  of  whirh 
IS  des(-rili«>d  in  antither  article  in  the  presi'iit  lunnlier  of  l*hytopath«ilofEy.  In  onW-r 
to  Ih*  Mire  that  rill  miitaminatinn  had  ocrurred  durinK  the  manipulation,  the  tuU'« 
after  tillniK  uen*  ke|»t  in  the  inrtitiatnr  fftr  two  days  at  ^tf)''(\  It  i*«  Udievrd  that  lhi« 
app:iratii!4  and  method  is  wnrthy  of  eonf<ideralile  employment  in  the  preparatimk  «>f 
cultiin*  media  for  use  in  plant  patlmlni^y. 

.1  *f  1*1  If,  iitif.mftiihit  t  >/<M  ^.  'rhe?«eMer4' prepared  in  the  following  manner  Smnd 
healthy  l>eet*i  Were  •<i-le(ted.  thoroughly  eleancd  and  immers4*d  in  iNiilmg  water  f^r 
three  minute^,  in  \]i\^  ^ay  !«terili7.inK  the  surface  hut  not  heating  or  chanKinx  in  .iti\ 
maniiiT  thr  ti>stie;*  dr»per  in  the  lH«>t.  They  wen'  thi'Ii  cut  into  sliren  mth  a  eafr- 
full\  -'rriii/ed  knif«'  Kaeh  ^li^e  Was  then  put  into  a  sterile  |N*tri  dtsh  ini«i  whirh 
pri'\  i<>ii-l>  lirilinaiN  inittient  a^ar  had  tn^en  poured. 

/iff'  i>  .-'.K.  '1  I. Ill  liuthlred  KTams  nf  lieet  leaves  were  cut  into  sm:i!l  piece  «  :%r.<l 
ImiiIi-iI  fur  an  hmit  in  (I  ;,  htrr  nf  uater.  W  ater  wai*  then  athh'd  to  make  up  tn  I  litfr 
aini  i<  f*  -'  iiiilifik!  !'<>r  !»•■  Imiir'*.  It  H:i<<  th«-n  tiltereil  thri»uith  ciitton  an<i  .*■<■>  t'«-  •>! 
tfii-  l.i«'  .\rrii*  i.|i|».l  til  1  litre  i»f  Iji'luu'?*  I'ft'th.  The  Ijeliic's  hmth  haii  prr%  i- 
«iii-l\  !'•«!.  p'lfiirij  in  I  In  fiitjiiw  mu:  May :  J  icrams  of  I.iehiK's  extract.  |n  g^ram*  i>f 
\\i'*i  iMji'-M  i!i'l  '•  k'?-ini- of  Mnliinn  rhloml  wiTf  addet]  to  1  litre  of  matrr  Thi« 
riM'i.iMi  ^^  •-  -  ii'«  ii'ii  ;.' \  III  iiM-ih/fil  tn  pheiinlphthalein  with  iMMiiuni  h\iiri>\i>l 
aii'i  ."•:  .•:-;.•!■:  ■!  ■!.•  1"«'  jui- •  \\a««  hritiiclit  up  In  O  .'»  yn^i  cent  acidity  with 
iii:i!.>  I  .•!  I  111  -  in.i  fill  •!:  irti  u  ix  al-n  pri*p:ire<|  with  an  increaMMl  |iropiirti«>n  nf 
!■• «  •  I  \*r  ■■•  * 


1917]  Boncqubt:  Bacillus  morulans  276 

Artificial  media.  A  protein-  and  peptone-free  medium  was  composed  with  the 
supposition  that  the  organism  did  not  attack  the  higher  nitrogen  compounds  of  the 
beet.  Therefore  several  of  the  amino  acids  were  used  as  the  nitrogen  supply.  Ala- 
nin,  leucin  and  tyrosin  were  used.  Asparagin,  although  not  an  amino  acid  was  also 
considered  a  possible  favorable  source  of  nitrogen  for  the  parasitic  organism.  All 
these  compounds  were  used  in  a  dilution  of  0.5  gram  to  1  litre  of  water.  The  neces- 
sary minerals  were  added  in  the  following  form  and  proportion: 

Magnesiimi  sulfate 0.2  gram 

Ammonium  phosphate 0.5  gram 

Potassium  nitrate 0.2  gram 

Calcium  hydroxid 5  cc.  of  a  saturated  solution 

Ferric  chlorid trace 

These  artificial  media  were  sterilized  in  the  Arnold  sterilizer  for  fifteen  minutes 
upon  three  consecutive  days.  Special  glycerin  and  glucose  media  were  also  pre- 
pared. For  this  purpose  1  per  cent  glycerin  was  added  to  a  part  of  the  asparagin 
medium.  So  also  5  per  cent  glucose  was  added  to  another  portion.  The  glucose 
medium  was  especially  used  for  anaerobic  purposes. 

Other  media.  Ordinary  media  such  as  nutrient  bouillon,  potato  glucose  bouillon, 
bean  pods,  milk,  litmus  whey,  nutrient  agar  and  nutrient  gelatin  were  prepared  ac- 
cording to  the  standard  methods. 

Methods  attempted  for  separating  parasites  from  the  plant 

In  order  to  separate  the  assumed  parasites  from  the  plant  and  obtain 
them  in  pure  culture  the  f ollowmg  technique  was  used  : 

Surface-disinfected  plant  parts  placed  in  culture  medium.  The  usual 
method  employed  in  this  sort  of  work  consists  in  soaking  the  tissue  to  be 
employed  for  a  given  length  of  time  in  mercuric  chlorid  and  then  washing 
oflf  the  same  with  sterilized  water  before  placing  the  tissue  in  the  culture 
medium.  A  need  of  standardizing  this  method  was  felt,  inasmuch  as 
there  is  no  assurance,  as  it  is  usually  described,  whether  on  the  one  hand 
the  disinfection  was  sufficiently  thorough  to  kill  all  smrface  organisms  or 
whether  on  the  other  hand  the  material  was  washed  sufficiently  to  remove 
all  the  mercury  and  prevent  its  being  carried  over  into  the  culture  medium. 
The  method  consists  in  dry  sterilizing  a  number  of  cotton-plugged  flasks 
of  50  cc.  capacity  or  any  other  desired  size.  At  the  same  time  larger 
flasks,  Ukewise  cotton-plugged  and  filled  with  distilled  water,  are  made 
sterile  in  the  autoclave:  Other  requisites  are  supplies  of  95  per  cent 
alcohol  and  1  to  1000  solution  of  mercuric  chlorid  in  water.  The  mate- 
rial from  which  cultures  are  desired,  after  thorough  wiping  with  cotton 
swabs  in  95  per  cent  or  absolute  alcohol  in  a  photographic  tray,  is  cut 
into  convenient  sized  fragments,  but  no  smaller  than  necessary.  These 
are  placed  in  one  of  the  empty  sterilized  flasks  and  covered  for  a  moment 
with  the  alcohol  for  the  purpose  of  removing  air  bubbles.  The  alcohol  is 
immediately  poured  off  again  and  the  flask  nearly  filled  with  mercury 


276  Phytopathology  (Vol.  7 

• 
solution  80  that  all  the  material  will  be  submerged.  This  is  allowed  to 
remain  for  the  desired  length  of  time,  depending  upon  the  nature  of  the 
tissue.  The  petioles  and  main  veins  of  sugar  beet  leaves,  especially  fairly 
old  leaves,  will  usually  stand  twenty  minutes,  but  with  leaf  bladen  and 
other  more  delicate  material  ten  minutes  has  been  found  the  maximum 
time  which  can  be  used  without  too  severe  burning.  Cut  surfaces  will 
naturally  absorb  more  of  the  solution  than  those  protected  by  the  natural 
covering  of  the  plant,  and  this  can  be  taken  into  account  both  in  con>id* 
eration  of  the  length  of  time  which  the  tissue  will  stand  without  being 
burned  by  the  mercur}'  and  also  the  time  neccKsary  for  washing  it  out 
again.  On  this  account  it  is  best  to  cut  the  tissues  as  little  as  powible 
before  disinfecting.  After  the  desired  time  has  elapsed  a  piece  of  brass 
wire  gauze,  l)eiit  to  form  a  cap  over  the  mouth  of  the  flask,  is  steriliie<l  in 
the  flame,  placeil  in  position  and  the  mercur>'  poured  off.  The  flask  is 
then  filled  with  sterilized  water  from  the  large  flask  and  the  water  of  this 
first  washing,  after  having  the  material  well  shaken  up  in  it,  is  poured  off 
imme<iiately  and  more  water  poured  in.  Tlie  pn>cess  of  pouring  off  and 
refilling  is  then  Continued  at  gradually  increaseil  inter>'als;  the  length  of 
each  must  depend  ui)on  the  nature  of  the  material.  It  was  found,  how- 
ever, that  if  the  amount  of  material  in  the  flask  is  comparatively  small  in 
proportion  to  its  capacity,  which  should  always  l)e  the  case,  six  changes 
of  water,  extending  over  a  |x^rioil  of  two  hours,  is  amply  suflScient  in  every 
casi\  In  this  case  the  first  five  changes  can  be  made  during  the  first  hour 
and  the  last  one  at  the  end  of  the  second  hour.  If  one  wishes  to  practice 
extreme  caution  the  mouth  of  the  flask  nmy  be  flame<l  an<i  the  cf>tton 
stopp<T  replaceil  after  each  change  of  water,  but  this  has  not  l)een  found 
ne<'i*ss:iry  so  long  as  the  amount  of  water  is  sufllicient  to  thoroughly  sub- 
merg(»  all  th(*  material.  In  our  work  the  wire  scret^n  is  usually  left  over 
the  mouth  of  the  flask  and  this  is  freshly  flanunl  l)efore  each  change  of 
water.  Aft4T  the  pnwess  is  completed  the  material  is  taken  out  of  the 
last  watrr  with  flanH^i  forceps,  hniken  into  small  pieces  if  necessar>'  an<i 
th<»rou^hly  rnish<^i  with  the  same  instruments  and  dropped  into  the  cul- 
tun*  licjuid. 

I*i*ct  culturta.  It  was  thouglit  tliat  a  gradual  adaptation  fn>ni  the 
plant  in  which  tht*  organism  is  living  to  the  me<iium  in  which  it  was  at- 
tempti'd  to  jjmw  it  nii^lit  I k*  ntMM»ssary  to  insure  success;  therefore  t he  di:^ 
eiuird  tir.Mi«-  was  so  tran>frrnMi  us  to  distiu^h  as  little  as  possible  the  cells 
of  tin*  l>«i*t.  Fnr  this  puri)os4»  glass  tuln^s  were  drawn  out  to  2  nun.  dianu*- 
Xvr.  \\XvT  >i«Tili/in>E  l>y  h<'at  tht'V  wt»n»  2iS4*iit icnlly  inserted  into  the  di*- 
e:LMMi  ir^ioii**  of  thr  Ui-t  to  a  d«*pth  of  1  rm.  The  tul>e  m'as  then  m*ith- 
drawn.  )>ririihn^  with  it  a  |)ortion  of  the  licM't  tissue  and  the  tenninal 
part  containing  tlir  tisMiu*  \v:l<4  can^fully  hniken  off  withsteriliied  forceps 


1917]  Boncqubt:  Bacillus  morulans  277 

and  dropped  into  the  medium.  In  this  way  both  ends  of  the  tissue  slightly 
protruded  from  the  glass  tube  and  came  into  direct  contact  with  the  cul- 
ture medium.  The  slow  diffusion  of  the  latter  was  supposed  to  secure  a 
gradual  change  of  habitat  in  such  a  way  as  not  to  hinder  too  severely  the 
growth  of  the  parasite.  Tissue  was  thus  removed  from  the  petiole,  from 
inside  the  root  and  from  the  larger  veins  of  the  leaf,  after  surface  sterili- 
zation with  a  flame  or  boiling  water,  afterwards  cutting  into  the  interior 
with  a  steriUzed  knife  and  then  introducing  the  glass  tube  to  take  out  a 
small  core  of  tissue. 

Results  of  isolation  experiments 

The  various  special  methods  described  were  carried  out  very  carefully. 
The  result  was  that  in  almost  every  instance  cultures  from  curly  top  tis- 
sue in  all  the  various  media  described,  and  especially  those  which  con- 
tained glucose,  showed  a  heavy  growth  after  twelve  hours  of  incubation 
at  20°C.  This  result  was  practically  imiform  wherever  diseased  material 
had  been  used.  Occasionally  growth  also  appeared  in  cultiu'es  from  sup- 
posedly normal  plants,  but  in  by  far  the  great  majority  of  cases  such  cul- 
tures remained  sterile.  This  seemed  to  indicate  that  the  organism  was 
not  peculiarly  difficidt  to  isolate,  judging  from  its  abundant  growth  on  such 
a  wide  variety  of  media.  Nevertheless  a  painstaking  work  was  imder- 
taken  in  order  to  complete  the  thorough  study  which  had  been  planned. 
The  anaerobic  cultures  also  proved  to  be  invaded  by  the  same  organism. 
Here,  however,  the  growth  was  less  abimdant  and  extremely  slow.  Sev- 
eral days  elapsed  before  any  colonies  were  visible.  A  great  deal  of  effort 
was  further  spent  on  work  with  all  kinds  of  media  but  always  the  same 
organism  grew  abimdantly.  Contaminations  naturally  occurred  now  and 
then  but  the  fact  was  most  decidedly  apparent  that  the  one  species  an- 
nounced by  Smith  and  Boncquet  predominated  in  the  tissues  of  curly  top 
plants  to  the  practical  exclusion  of  all  others.  The  special  culture  meth- 
ods described  above  are  given  in  some  detail,  inasmuch  as  they  may  con- 
tain suggestions  of  value  in  similar  work.  Having  foimd  that  this  organ- 
ism grew  so  easily  and  abundantly  upon  ordinary  media,  the  use  of  special 
preparations  was  abandoned  in  the  attempts  to  isolate  the  organism  from 
plant  tissues  and  the  work  was  carried  on  entirely  with  standard  bouillon 
to  which  5  per  cent  glucose  had  been  added.  The  object  of  the  glucose  was 
to  promote  the  growth  of  the  characteristic  zoogloeae  of  this  organism, 
rendering  its  identification  in  the  original  tubes  easy  without  plating.  By 
occasional  plating,  as  a  check  on  the  work,  it  was  soon  possible  to  identify 
this  organism  very  accurately  by  microscopic  examination  of  tubes  which 
showed  the  characteristic  ring  formation  at  the  surface  of  the  Uquid.    The 


278 


Phytopatholoot 


(Vol,  7 


TABLE  1 
Results  of  bacterial  isolation  experiments  by  cultural  methods 

(Tul)eB  incubated  at  28H!).    Disease  meant  curly  top) 


MATSKIAL 

NtJiiBSK  or 

TVBBS 

•■irut 

Petioles  of  curly  top  beets 

6 

5  tubes  developed   B.  wwrulans 
within  two  days 

Petioles  of  normal  beets 

6 

Tubes  remained  clear  for  a  w#rk. 
when  they  were  discarded 

Petioles  of  diseased  l>eets 

9 

8  tubes  developed  morulans 

A  leaf  showing  curly  top  symp- 

5 

All  developed  marulanM 

toms  on  half  of  blade  and  in  cor- 

respondinK     half     of     petiole. 

Other    side    appeared    normal. 

This  material  from  affected  half 

. 

of  petiole  with  black  streaks 

Correspondinfc  half  of  blade 

3 

2  tul)es  developed  morulanM 

Normal-appearinK  half  of  petiole 

6 

5  tubes  developed  morulant  two 
days  Inter  than  those  from 
blackened  part 

Norinal-appcHrinK  »ide  of  blade 

3 

No  development 

Petiole  of  a  diHcascd  center  leaf 

4 

3  with  mofu/anir.  1  doubtful 

Petioles  of  good-sized  leaves  from 

10 

2  tul)es  frr>m  1  leaf  both  with  morw 

5     different     n(»nnal-appearinf( 

lann;  others  all  clear 

i>eeiM 
Typiejilly  diseased  leaf  with  very 

6 

All  developed  mtrrulans 

slight  dark  streaks  in  the  jM'tiole 

Badly    affected    {wtiole    of    name 

4 

All  develope<l  morulans 

iM'et.          Pieces    rut     out     with 

flamed  scalfx'l 

Petioles  nf  4   beets   from   ins4'Ct- 

8 

Tulies    from   2    plants    remained 

pronf  cagt*.     No  sign  of  diseaM^ 

clear ;  those  f mm  other  2  lieramr 
slightly    cloudy    after    m-vrral 

• 

days,  but  no  mi^rulana 

PftioIrK    <»f    2    slightly    dis<»as<'d 

13 

All   tul>es  apparently  r«mtaininK 

Irrivi--*.      Pierrs     rut      (»llt      with 

pure  cultures  of  mttrulana 

tl.iMH'ii  .Hr:tlpcl 

A  >fll«i\\i-h  :i>t«T  leaf 

o 

Ilemained  clear 

Afi  «'l«l  yillnwirih  biM't  li'af  without 

4 

S<»me  fungous  growth.    No  morb- 

•Mirly  top.     Tissue  still  s<»u!id 

tans 

!>•'.•» v«'«i  i»f  ri  snrnewliat   abnonnal- 

0 

Some  growth,  but  no  iiMiriiiij»i« 

:ippi'ir:iig     tn-rt      but      Dot      With 

<MirI\   top 

I!i:i!*h\  -  ij>pt  -iriHt:  !r:ivr>  <»f  aster, 
i  I.:  *.  »  t:<7|ii  iii'iiii  •irihli:i.  ti>iiia- 
*  ■    *  •  .»fi    !•■•  t ut  •■  ritnl  r.iddith 

I't*i"!i    i.t  '\pi<  ill\    •ii-f:iHiM|  livif. 

t.i-   -ii  -lltli  ■  •  ;-.!i 


24         ill  tubes  with  fungi  and  l>artrriA. 

remainder  clear.     No  m«>rW«in« 

I      founti 

(i  Very  abundant  growth  of  mi^^a^t 

intermixf*<l  with  other  organ usn* 


1917] 


Boncqxtet:  BACiUiUS  morulans 


279 


TABLE  l-Continuei 

IIATSRIAL 

NT7MBKB  Or 

TUBM 

BK8ULT 

Petiole  of  slightly  diseased  leaf 

2 

Both  very  abundant  morulanB 

Blade  of  same  between  veins 

2 

Both  remained  clear 

Typically  diseased  leaf;  scraped 

4 

3    tubes   developed   morulans,    1 

out  interior  portions  of  petiole 

doubtful 

with  flamed  scalpel  after  clean- 

ing off  epidermis 

A  young  leaf  visibly  affected  on 

4 

All  developed  morulans 

one  side  and  very  slightly  at 

the  base  of  the  other  side.    Tis- 

sue taken  from  the  most  dis- 

eased side  at  base 

Terminal  portion  of  diseased  side, 

4 

2  developed  mortdans;  2  clear 

less  visibly  affected 

Slightly  affected  base  of  other  side 

4 

1  developed  morulans;  3  clear 

of  same  leaf 

Not  visibly  affected  terminal  por- 

4 

All  remained  clear 

tion  of  last 

Note.— The  last  four  are  from  the  leaf  illustrated  in  Phytopathology  6:  106. 
The  most  elaborate  precautions  were  taken  to  secure  perfect  surface  disinfection  and 
avoid  contamination.  These  tubes  in  which  gprowth  appeared  were  plated  out  and 
found  to  contain  pure  cultures  of  morulans.  The  leaf  was  perfectly  sound,  showing 
only  a  slight  roughening  of  the  veins  on  the  affected  portion. 

appearance  to  the  eye  of  this  ring,  supplemented  by  microscopic  examina- 
tion, finding  it  to  be  composed  of  the  characteristic  zoogloeae,  supple- 
mented by  occasional  plating,  is  amply  sufficient  to  identify  this  organ- 
ism. A  number  of  typical  examples  of  isolation  experiments  with  sugar 
beets  are  shown  in  table  1. 

Several  himdred  illustrations  similar  to  those  shown  in  table  1  might 
be  given.    The  results  varied  somewhat  with  the  perfection  of  technique 

TABLE  2 
Bacillus  morulans  upon  sugar  beet  seed 


MATERIAL 

NUMBBR  or 

TUBES 

RESULT 

Beet    seed    imported    from    Ger- 

10 

At  least  7  developed  an  abundance 

many,  1  dropped  into  each  bouil- 

of morulanSf  mixed  with  other 

lon  tube,  with  no  previous  treat- 

organisms 

ment 

Similar  seed  previously  soaked  for 

10 

All  clear 

twenty    minutes    in    mercuric 

chlorid  and  washed  in  sterilized 

water 

280 


Phytopathology 


[Vol.  7 


and  in  individual  cases,  but  a  mass  of  evidence  was  collected  to  indicate 
that  this  organism  exists  regularly  in  the  interior  of  the  foliage  of  migar 
beets  where  the  visible  s^^mptoms  of  curly  top  occur  and  that  it  does  not 
develop  in  cultures  from  nomud  foliage  or  even  the  normal-appearing  por- 
tions of  partially  affected  leaves;  also  that  it  does  not  occur  in  the  interior 
of  beet  leaves  which  may  be  yellow  or  sickly  from  ordinary  cauM«. 

Cultures  from  seed.  Many  attempts  similar  to  those  shown  in  table 
2  were  made  to  isolate  the  organism  from  sugar  beet  seed.  The  uniform 
result  was  that  almost  every  unsteriUzed  beet  seed  dropped  into  a  tube 
of  lx)uilIon  developed  a  very  luxuriant  growth  of  Bacillus  fnarulans, 

TABLE  3 
liacillim  tmnulann  from  noil 


MATCRIAI. 

NruBBR  or 

TCBCn 

KaBn.T 

Pinches   of  soil    from   alxmt   the 

r(H)t8  of  a  diseased  l)eel 
Pinches   of   soil    from   about    the 

roots  of  a  normal  U'ct  in  insc»ct- 

pnK>f  cajje 

4 
4 

Marulana  wm  abundant  in  tpverml 

of  the  tul)e« 
Some    morulan9    present    in    the 

mixed  growth  resulting 

Culiurenfrom  soil.  That  the  organism  is  present  in  some  soils  is  indicated 
by  tho  data  preK»nted  in  table  3.  The  work  was  rather  crude  but  cer- 
tainly li.  tuorulans  was  abundant  in  the  soils  examined. 

Cultures  from  unsteriUzed  foliage.  Cultures  made  from  unsterilised 
leaves  of  the  sugiir  In^'t  (table  4)  show  that  the  organism  is  common  as  a 
sapro|)hyte  upon  the  leavt^  of  the*  plant,  but  in  all  cases  when  leaves  simi* 
lar  to  these  w<Te  thoroughly  disinfcvted  no  growth  was  obt^ned. 

TABLE  4 
CuUnrf*  from  unntfrilizrd  foliage 


M\ri  HI«L 


I.<-:ivi*«»  i»f  iiortiial  iHTtH 


Ni'MBCR  or 
Ti'Bm 


10 


saicxT 


several  contained  an  abundance 
(»f  moridanM 


rii>t«'riliz(Hl  loavt*^  of  many  other  plants  were  also  tried  but  the  resulting 
grtiUlh  \%:i>  Ml  luixod  that  no  safe  rtiiirhisions  (*ouhl  1m»  drawn.  The  only 
rertaiii  iicvt*Inpiiu>iii<  of  muruUius  (NTiirnMi  in  tnU's  inoculated  with  pieces 
of  r)in>anth('iiuuii  h*avi'.<. 

i'ulturtt^  frttm  suijtir  /w«/  Imns  tnth  ty/Ms  of  disease  other  than  curly  top. 
Th«-  I'art  that  lM»ilit>  n'x-iiihliiiK  bacteria  have  b4M»n  s<»en  i*ith  ihe  micro- 
iii*ii|H'  in  sii^jir  Ui't  h'av«->  not  afTt-t-t^Hl  with  curly  top,  Init  affected  with 


1917] 


Boncquet:  Bacillus  morulans 


283 


TABLE  5 
Cultures  from  sugar  heel  leaves  with  types  of  disease  other  than  curly  top 


MATERIAL 


Yellowish  area  of  young  "black 
edge'*  leaf  taken  from  between 
black  and  green  portions. 
Thoroughly  disinfected 

Similar  to  last,  but  not  disinfected 

Similar  material,  disinfected 
Similar  material,  disinfected 
Typical  "mottled  leaf;''  not  dis- 
infected.   Blade,     petiole    and 
veins 
Petiole  of  "black  edge"  leaf,  dis- 
infected 
Petioles  of  normal  appearing  leaves 
from     healthy     plant.        Very 
carefully  disinfected 
Petiole    of    decidedly    "mottled 
leaf."    Inner    tissue    removed 
with  flamed  scalpel 


RESULT 


Both   gave    a   strong   growth   of 
morulans 


Very  vigorous  and  apparently 
nearly  pure  growth  of  morulans 

All  with  morulans 

All  with  morulans 

All  produced  morulans  in  abun- 
dance 

All  appear  to  have  pure  cultures 

of  morulans 
All  tubes  clear 


Very  vigorous  growth  of  morulans 


Further  study  of  the  organism,  which  was  uniformly  present  in  diseased  beets 

Although  the  organism  was  able  to  grow  most  abundantly  on  the  com- 
mon culture  media,  the  peculiarity  of  this  growth  under  all  circumstances 
was  of  such  a  nature  that  for  some  time  a  continual  contamination  was 
suspected.  Each  separate  colony  seemed  always  to  have  two  kinds  of 
bacteria,  very  distinct  in  form.  Very  active  bacteria  were  always  observed 
at  the  edge  of  the  colonies,  while  capsultated  bacilli  were  generally  ob- 
served in  the  middle.  Therefore,  before  any  further  study  of  the  organ- 
ism was  taken  up,  repeated  efforts  were  made  to  separate  these  two  widely 
distinct  forms.  For  this  purpose,  the  calcium  carbonate  and  the  India 
ink  method  for  separating  the  individual  organisms  previous  to  plating 
them  were  resorted  to. 

Calcium  carbonate.  To  10  grams  of  calcium  carbonate  enough  water 
was  added  to  form  a  milky  paste.  This  was  subsequently  introduced  into 
a  200  cc.  Erlenmeyer  flask  and  sterilized  in  the  autoclave.  After  the  nec- 
essary cooling  several  yoimg  colonies  of  the  bacteria  were  introduced  into 
the  semi-liquid  mass  and  shaken  for  two  hours  so  as  to  separate  each  indi- 
vidual organism  from  the  other.  From  this  paste,  several  plates  were 
poured  in  the  usual  manner.  They  were  incubated  at  37°C.  and  closely 
examined  as  soon  as  any  sign  of  development  occurred. 


284  Phytopatholoot  [Vol.  7 

India  ink  method.  For  this  purpose  special  Chinese  ink,  prepare«l  by 
Grilbler,  (Punkttusche)  was  used.  A  15  per  cent  nutrient  gelatin  was 
made  and  poured  into  clay-covered  petri  dishes.  Special  care  was  given 
to  prevent  condensation  water  from  flooding  the  medium.  The  GrQbler's 
ink  was  diluted  twenty  times  with  n/6  glucose  solution  and  sterilised  in 
the  autoclave.  In  a  sterilized,  empty  petri  dish  ten  drops  of  the  ink  were 
put  in  a  row.  The  first  drop  was  inoculated  with  a  small  amount  of  bac- 
teria from  a  twelve-hours-old  streak  culture.  The  bacteria  were  thor- 
oughly mixed  with  the  ink  of  the  first  drop.  Then  a  loop  of  this  was  trans- 
ferred to  the  second  drop  and  also  thoroughly  mixed.  This  transfer  was 
repeated  in  the  same  way  with  the  remaining  drops  in  the  dihh.  From 
the  tenth  drop,  with  a  sterilized  drawing  pen,  a  small  amount  was  taken. 
Small  (lots  were  made  with  the  pen  on  a  gelatin  plate  in  such  a  way  that 
the  surface  pellicule  of  gelatin  remained  uninjured.  These  ink  dots  were 
left  to  dry  for  two  minutes  then  covered  with  a  sterilized  cover-glass.  A 
small  drop  of  immersion  oil  was  8ul)sequently  applied  to  the  cover-glai« 
and  the  whole  pt^tri  dish  was  i)rought  to  the  microscope  for  examination. 
Each  black  p<jint  wa.^^  then  examine<l  \^'ith  microscope  until  one  was 
found  which  containoil  one  single  organism.  The  organism  appeared  as  a 
translucent  dot  on  a  black  field.  Its  development  was  closely  foUom-ed; 
the  first  division  was  distinctly  noticed  after  half  an  hoiu*;  it  muhiplied 
rapidly;  all  the  individuals  were  motile;  they  liquefied  the  gelatin  riightly 
and  nioveil  alK)ut  ver>'  briskly  in  the  liquid  under  the  cover-glass.  After 
six  hours  some  of  the  organisms  l)ecame  sluggish  and  gradually  k)st  their 
motion.  They  incn*a.'*<Ml  in  size  and  forme<l  a  capsule.  Repeatedly  they 
divide<i  in  the  same  capsule,  stretching  the  jelly-like  membrane  more  and 
more.  The  newly  forme<i  organisms  within  the  original  capsule  also  en- 
ca|)sulated  in  their  turn  (figs.  0  and  7).  At  the  same  time  the  indi\idual8 
on  tlic  rim  of  the  colony  multipliefi  and  remaine<i  mcvtile.  The  double 
form  of  the  bacillus  was  in  this  way  clearly  explaincMl  and  pn>ve<l. 

IDKNTITY   OF  THK   OKCANIHM    FOUND   IN   TURLY  TOP   BEETS 

\  Study  of  the  litcnitim'  of  the  subje<-t  shows  that  the  greatest  similarity 
to  our  organism  (»f  any  descrilN'd  s|K'ci<»s  is  presented  by  that  descrilieil  by 
.\nhur  and  Holl(*y^  as  liacUrium  Dianihi  as  the  cause  of  a  leaf  spot  of  the 
caniatic»n.  In  its  morpholog}'.  so  far  as  descrilKxl  by  these  writers,  this 
organ i;4iM  is  v(*r>'  similar  to  ours,  the  n*semblanc<»  lieing  nmde  pronounced 
by  thf  (i«-veIopinent  <if  characteristic  z<M)gl(H*a<'.  In  biological  liehavior, 
Imwrver.  the  iwo  or^canisins  cannot  Im'  accurately  compared,  since  the 

*   \rttiiir.  .)   i'    :ini|  liiillfv.  II.  L.     HiirtrriiMiiN  (»f  rnriintioriii.     Indi»n»  .\Kr.  Kxp 

St:i     lilt  I     .v.*        IVHi. 


1917]  Boncquet:  Bacillus  morulans  285 

work  of  Arthur  and  Bolley  was  carried  on  at  a  time  when  bacteriological 
technique  was  not  standardized  upon  modem  lines.  One  noticeable  dif- 
ference exists  in  respect  to  growth  upon  an  acid  medium,  B.  DiarUhi  being 
said  to  grow  best  under  such  circumstances,  which  is  not  the  case  with 
our  organism.  The  description  of  the  bacterial  organism  given  by  Arthur 
and  Golden^  and  again  by  Miss  Cimningham^  as  the  cause  of  the  so-called 
Indiana  sugar  beet  disease,  is  similarly  subject  to  imcertainty,  but  if  this 
work  was  accurately  done  the  organism  must  certainly  have  been  differ- 
ent from  ours  in  that  it  is  said  to  be  a  particularly  active  gas  former,  which 
feature  is  totally  lacking  in  our  organism.  It  seems  proper  to  mention 
here,  however,  the  fact  that  Professor  Arthur  in  a  recent  personal  letter 
states  that  the  accuracy  of  all  this  early  work  performed  under  his  direc- 
tion is  open  to  some  doubt  on  accoimt  of  the  imdeveloped  condition  of 
bacteriological  technique  at  the  time  and  he  expresses  the  opinion  that 
the  organisms  found  by  Bolley,  Miss  Golden  and  Miss  Cunningham  were 
very  likely  identical. 

The  organism  described  in  the  unpublished  work  of  Schneider*  as  BaciU 
liLS  califomienaiSj  which  was  isolated  from  curly  top  beets  in  California, 
seems  again  in  its  morphological  characteristics  to  be  entirely  similar  to 
ours  and  we  feel  little  doubt  that  Schneider  and  the  present  writer  had 
the  same  organism  before  them.  Schneider  found  his  organism  also  very 
abundant  in  sugar  beet  soils  and  upon  the  surface  of  the  plants.  He  at- 
tributes a  stimulative  effect  to  this  species,  when  applied  in  pure  culture 
to  sterilized  beet  seed  or  to  the  foliage  of  yoimg  plants. 

The  organism  described  by  Dtiggeli*  as  being  abimdantly  and  often  ex- 
clusively present  upon  the  surface  of  various  plants  and  seeds,  seems  also 
very  similar  to  ours  in  form  and  size,  formation  of  zoogloeae,  color,  sapro- 
phytic habitat  and  most  biological  characters.  This  was  named  by  Diig- 
geli  Bacterium  herbicola  aureum,  but  "said  to  be  the  same  as  the  BaciUus 
meserUericus  aureus,  isolated  by  Winkler  from  the  surface  of  plum  leaves." 
The  latter  statement  confuses  the  identification. 

DESCRIPTION   OF  THE   ORGANISM 

Summing  up  the  whole  situation,  we  feel  justified  in  describing  oiu: 
organism  as  a  new  species  on  account  of  the  incomplete  and  doubtfully 

*  Arthur,  J.  C.  and  Golden,  K.  E.  Disease  of  the  sugar  beet  root.  Indiana  Agr. 
Exp.  Sta.  Bui.  39,  pt.  3:  54.    1892. 

^  Cunningham,  C.  A.  A  bacterial  disease  of  the  sugar  beet.  Bot.  Gas.  28:  177- 
192.    1899. 

'  Schneider,  A.  The  California  beet  blight.  Spreckels  Sugar  Co.  Exp.  Sta. 
Rept.  28:  — .     1906.     (Unpublished.) 

•  Centbl.  Bakt.  II,  12:  602  and  695;  18:  56  and  198.     1904. 


286  Phytopathology  [Vol.  7 

accurate  descriptions  of  those  species  which  more  or  less  rcsemblo  it .  ami 
the  fact  that  none  of  them  corresponds  throughout. 

Bacillus  morulans  n.  sp. 

Morphology 

Vegetative  cells.  Grovm  in  Liebig  bouillon  for  sixteen  hours  at  aUiut 
20°C.,  oval  to  short  rods,  single  or  in  pairs.  Groim  at  37*,  shoft  rrMb  in 
pairs  or  in  short  chains. 

Sizi'.     Length  1.5  m;  breachh  0.1)  n:  extreme  length  from  1.5  to  2  m- 

Capsules.  Kasilv  observed  in  1  lOCK)  glvcerin  iKmillon  after  twenty- 
four  hours  and  also  in  milk  nuKlia  (figs.  6  and  7). 

Motility.  Very  active  on  agar  and  in  l>ouillon,  when  grown  at  37'  for 
twelve  hours. 

FUujella.  StaiiuMi  by  Z<»ttnow*s  meth(Hl;  four  long  peritrichial  flagella 
(figs.  G  and  7). 

PU'omorphism.  Cocciforius  obstTved  in  glucose  Inmillon  tulles  and 
bloo<l  s<»niin  nie<iia  after  thirtv  davs. 

Stain.     Miisilv  with  waterv  fuchsin,  d(H*olorize<l  bv  CSramV  m€*thcNl. 

Cultural  features 

(ielatin  platv  mutral  to  phenol phthalein,  Konn.  round  to  irregular; 
surfa<*(»  elevation.  Hat  to  convex  contoure<l;  internal  Mnieturv,  refnuiion 
strong,  hyalin**,  inoruloid;  zoogl(K»ae  very  marke<l;  tHlgi*s.  entire  to  undu- 
late: optical  characteri.<tics  transparent  to  butynnis;  consistency.  \'u*ctm.*. 
Kacli  colony  is  surrounded  with  many  .^'condary  colonies,  appearing  a.H 
sniall.  «»ily  drops  of  high  refra<'tiv<*  power.  The  appearance  of  so(»gloeaf 
is  verv  noticeable  in  the  middle  of  the  cohmii'S. 

(it  hit  in  plntfs  I  ..'t  oeid  tn  phvnolphthalein.  The  entire  nuM»  is  a  xooghM^a, 
IoIn'iI  and  irregular  in  outline;  the  colony  is  slightly  colored;  orange-yrl- 
Inw.  !in  >iirroun«liiiu  ro|nni«»s  noti(*e<l. 

fnhit'f,  stnnk.  After  five  days:  gro\\lh,  linear;  margin,  continuoiL«; 
surf.-m-  iriji-f,  flat  i<»  eiuivex:  li^Jht  transmissi<»n.  butynius;  t*olor.  yellow- 
oraii^*-:  lu-^trr.  ^li-trninj::  cimsi^tency,  visi-ous.     The  water  of  conik*n«&a- 

tinii  ha^  :i  yrjinw   >4Mliiiieiit . 

ft't  iitt.    /i.'/».     Aft  IT  twi'iity-twn  h«»urs.  top  gn»wth:si£e.  5  mm.,  im^ilAr 
('(iiiiciit*'d    pulvinate  tn  capitatr.  li^lit  orangt*  in  color;  vis(*ous  in  coiLM^t 
<*in\  .  'ii-tti  ^liiiiiim. 

(,..>'  /  ^ti,ttl .  I'ilifnrin  tn  slinlitly  iM*adi'd.  .\fter  fifteen  <lays.  liquid 
f.f  Ml. ii  «.i  iiii'diuiii.  rratrrifnrm  with  a  vellow  s4Miiment.  After  Iwenlv 
iii>-.   li«j»i«  fretimi  ytratiforiu;  yellnw  pigment.  decreas<M|  by  alMtenci*  of 


288  Phytopathology  [Vol.  7 

Agar.  The  colonies  are  extremely  variable  according  to  the  deniQty  trf 
growth,  the  moisture  and  the  t-emperature. 

Milk.  Peptonisation  of  casein  in  fifteen  days  at  37®.  The  re«iclMm  w 
alkaUne  to  Azolitmin. 

LitmuH  xvhcy.     Remains  clear,  alkaline  reaction. 

Bouillon  Uibea.  Opacity  l)egins  after  eight  hours  at  37**,  a  pellicule 
fonns  in  twenty-four  hours  or  less.  The  color  of  the  pellicule  antl  the 
ring  is  dull,  soft  gray ;  thick,  viscous  and  conaists  of  oongkimerate  leogloeiir. 
The8e  are  generally  oval,  but  may  l)e  linear  and  all  united  in  ehainii. 

Deposit,  forms  after  two  days  incubation  at  37**.  I>epoKit  is  in  the 
lK*ginning  slight,  and  finally  yellow.  The  amount  of  deposit  and  the  in- 
tensity of  the  color  increases,  how<*ver,  rapidly.  After  t*»n  days,  a  de- 
cidedly d(»ep  yellow-orange  has  develofx'd.  The  de|MK<it  is  compact  and 
viscid  on  agitation. 

Potato  streak.  After  twenty  four  hours  at  37**.  Size,  2  nun.;  sharp. 
linear;  margin,  continuous;  color,  yellow,  honuM*hn)mous ;  lust<T,  glisten- 
ing; texture,  homogencHnis.  Xo  Hcjuefaction  of  |)otat<»  and  no  gat 
formation. 

Physical  a  tut  biochemical  features 

Heaction.  In  carl M)hy drat <'-fre<»  nuMiia  the  reaction  is  alkaline;  in  carlMH 
hydrate  media,  the  reaction  is  acid,  except  in  lactos4»,  where  the  n*action 
is  .slightly  alkaline.     S«m»  table  <>. 

\ Urate  Liebig  broth.  After  twenty-four  hours  at  37',  stnmgly  nNhice^l 
to  nitrite. 

ludol.     Not  pHMiuaMi  in  p<*ptone  solution  after  ten  days. 

Optimum  temfnrature.  37**,  meju^unnl  by  the  amount  of  acid  pnMiu<'«'d 
in  1  JMT  <'ent  glu<*os4*  after  five  days.     Acidity  w:l»*  2.5. 

Thermal  death fmint.    Six-hours  culture  in  iMmillon;  i'A'^i  \  in  ten  minui<*9». 

Carlnth  yd  rate  fermentation.     Shown  in  table  ti. 

lirsistanee  to  mercuric  chloritl.  Six-hours  <*ultun'  on  iKiuillon  agar  stn^ak 
killc<l  in  1  2:>.(NN)  to  1  ;i(MMM)  in  ten  minut<^. 

Ut latter  growth  in  acid  and  alkalin  media.  IX*tennin(H|  by  the  ap|M*:ir- 
aiKM*  of  cloudinos  in  the  tulH>.  (Sniws  bc^t  cm  neutral  or  slightly  idkalin 
mrdia.  Vwv  \h't  cent  in  ari<l  appan'ntly  stops  all  gnmih;  7  per  ei-nt  in 
alk:tlin«':  >am('. 

<ffi>  piiuhu'tnni.     No  gas  i>  pHNJuctMl.     Sim*  tabic  G. 

litlntittu  tit  frtt  oiygtn.     AiTobir;  facultative  anaerobic. 


1917]  Boncquet:  Bacillus  mordlanb 


TABLES 

CarbohydTate  /ermentation  of  BaeiUui  morulana 
(Incubation:  37''C.,  medium  neutral  to  aiolitmin) 


NoTx. — A,  acidi  B,  basic;  p,  permanent;  b,  abundantly  present;  a,  absent;  x, 
more  or  less  present;  *,  acid  on  top  and  basic  in  tuho. 

PathogeneaU 

One  loop  from  a  twelve-houre-old  streak  culture  on  bouillon  ^ar  intro- 
duced intravenously  in  a  rabbit,  caused  death  within  twenty-four  hours. 

On  Diajithus  incamaUi.  The  young  unfolded  leaves,' when  unrolled  and 
covered  with  an  abundant  suspension  of  bacteiia,  developed  small  necrotic 
r^oDS.  The  necrotic  regions  are  watery  and  translucent  on  the  edges, 
slightly  elongate  or  irregular  in  outline,  following  the  venation.  The  in- 
side of  the  necrotic  r^ons  is  sUghtly  brown. 

UmvBBsnr  or  Caufoknia 
Bebkelet,  Califoknta 


A  NEW  APPARATUS  FOR  ASEPTIC  ULTRAFILTRATION 

Ralph    E.    Smith 
With  Two  Fiquees  in  the  Text 

In  various  investigations  of  so-called  nonparasitic  or  phyaological  plant 
diseases,  as  well  as  in  numerous  animal  diseases  in  which  the  pmence 
of  an  ultramicroscopio  organism  is  suspected,  the  juices  or  body  fluids  of 
affecte<l  plants  or  animals  have  often  be<  n  subjected  to  filtrmtion  through 
Berkefeld,  (^haml)erlan(l  and  similar  filters  in  order  to  remove  bttcteria 
and  other  organisms  of  microscopically  visible  size.  While  inocuUtions 
with  such  filtere<i  juice  have  lxH*n  made  frequently,  and  in  some  cases 
(tobacco  mosaic)  with  i)ositive  results,  the  possibility  of  dcmonstniting 
the  presence  of  a  t)nrasite  in  the  filtered  juice  \iy  its  poosiUe  growth 
when  all  other  organisms  an'  excludeil,  se<*ms  to  have  received  little  at- 
tention so  far  as  plant  diseases  are  concerntHl. 

Another  object  in  pnnlucing  an  aseptically  filtered  juioe  is  that  of 
obtaining  a  st^Tile,  unheat<Ml  plant  extract  as  a  culture  medium,  as  men* 
tion(*<l  by  Mr.  B<>nr({uet  in  another  article  in  this  number  of  Ph>'to- 
path()log>'.  In  either  cast'  the  juice  may  l)e  varied  in  concentration  or  re- 
action, any  desinul  substance  which  will  pass  through  the  filler  may  be 
addtnl  to  it.  an<l  in  many  ways  ilh4*  may  hv  found  in  the  investigation  of 
plant  diM>as<*  f(»r  tisi^ptically  filtennl  and  preserved  or  ooM-ffteriliaiHl 
jui(M\s.  Various  devict^  for  this  purpose^  have  l)een  described  but  all 
of  them,  HO  far  as  the  writ<T  is  aware,  an*  clums}'  and  of  very  doubtful 
efficiency.  Those  in  which  the  candle  and  the  Uquid  to  be  filtered 
in  11  tulN*  <iin*rtly  aUive  th(*  receptacle  or  outlet  for  the  filtered  juice 
esiMM'inlly  uiidrsirahle.  since  the  slightest  leakagf*  may  result  in  contam- 
in.HtiiiK  the  filtrate  with  the  unfiltenHi  juice  and  thus  d<*feating  the  whcilc* 
objtrt  of  filtration.  HiiblNT  stop|)ers  an*  alwa>'s  op4*n  to  sus|Nci4m. 
ArranK«inentH  ju  whieh  the  filtrate  is  caught  in  an  opi*n  or  a  cutton- 
stopiMii  ve>Ml  and  then  iM>ure<i  into  the*  cultun*  tul)es  in  the  open  air 
are  eiTtaiiily  far  fmm  safe.  Those  in  which  the  liquid  is  forced  thmugh 
the  raiiiilf  fri»in  the  iiL-iide  outward  are  obj«H*tionjible  on  account  of  the 
quirk  eujitii»K  ovt  r  of  the  inner  surfaer  with  sentiment ,  which,  on  the  i»ut- 
>ii\r.  may  Im-  iimMly  Imishid  off.  In  the  ap|)aratus  illustrated  hen*  the 
only  )Hi>-.il>ility  ni  <*ontaiiiination  is  fri»ni  the  air  and  cannot  occur  fn>m 
th<  \ihfUti  n  tl  juicf.     Ill  4  it  her  words,  it  is  abs<ihitely  c<-rtain  that  nothing 


292  Phytopatholoot  (Vol.  7 

in  the  line  of  tubing  from  the  candle  to  the  upper  reservoir  are  wrapped 
closely  with  cotton,  extending  beyond  the  ends  of  the  rubber  connections 
and  for  about  an  inch  down  over  the  candle  itself.  Over  these  an*  put 
again  still  longer  cotton  wrappings  and  finally  a  layer  is  put  on  covering 
the  whole  line  completely  from  a  point  two  inches  bdow  the  upper  end 
of  the  candle  up  to  the  reservoir.  The  whole  region  around  the  fKUip- 
cock  is  similarly  wrapped  with  several  layers  of  cotton,  with  a  largi*  plug 
of  the  same  material  in  the  lower  opening  and  a  wrapping  over  this  and 
up  arotmd  the  tube.  It  is  the  intention  that  all  the  joints  shall  be  air- 
tight and  in  this  apparatus  the  number  of  joints  and  chances  of  con- 
tamination arc  less  than  in  most  similar  devices.  (Compare  for  example 
the  arrangement  figured  on  page  65  of  Marshall's  Microbiology.)  The 
cotton  wrappings  are  added,  however,  as  an  extra  precaution. 

After  the  apparatus  has  been  put  together  and  wrapped  it  b  sterilised 
in  the  autoclave.  At  the  same  time  a  supply  of  cotton-phigged  tf-nt- 
tul>o8  is  Rterilized  by  dr>''  heat.  The  apparatus  is  then  set  up  on  a  taMe 
convenient  to  a  gas  burner  and  some  of  the  juice  to  be  filtered  pourrd 
into  the  l)eaker,  taking  cure  not  to  allow  the  cotton  at  the  upper  end  of 
the  candle  to  touch  the  li(|ui(l.  The  water  vacuum  pump  is  starteil. 
using  as  little  suction  as  po8sil)le,  and  allowed  to  operate  until  a  supply 
of  the  filtered  juice  has  l)een  collected  in  the  reservw*.  If  the  aurfare 
of  the  candle  iK'comes  Uh)  much  clogged  it  may  be  cleaned  with  a  soft 
brush,  but  it  is  (l(*sirable  In^fore  commencing  the  filtration  to  remove  as 
much  solid  maU^rial  from  the  juice  as  possible  by  filtering  through  cloth. 
pa|MT  and  sand.  As  soon  as  enough  juice  has  l)een  filtered  the  cott4m 
phiK  dosing  the  lM)ttoin  of  the  main  tul)e  is  removed;  one  of  the  steril- 
ized test-tubes  is  h<'l(l  in  imv  hand,  the  plug  n>moved  and  discarded,  the 
tiilx*  thoroughly  flaineil  s<*v(*ral  inches  do^Ti  from  the  top  and  then  panst^l 
up  int4>  the  lowrr  end  of  the  ap]mratas  ]N*h>w  the  outlet  tube.  With  the 
other  hand  the  stoiw'ock  is  tum(*<l  and  some  of  the  liquid  run  intoth«* 
tulM'.  Aftrr  shutting  off  the  cork,  another  tulH»  is  taken  from  the  ))ask«-t 
with  that  hand,  whilt*  the  tulx*  just  RIUhI  is  withdrawn  and  its  open  enil 
hiM  in  the  f1:iine.  Th<'  ])luK  of  no.  2  is  now  transferre<l  to  no.  1.  Nith 
tiilMS  ronstaiitly  flaiiieii.  no.  1  is  laid  aside  and  no.  2  filled,  continuing 
th»*  pn»e«->s  with  as  ipimy  tnU-s  as  «lesired. 

Tht  apparatus  fiKtirtMl  is  14  inches  long  over  all«  and  holds  200  rr.  «if 
li«|iii«l.  DitTiTi-nt  <izis  may  of  r«iiirse  Im»  n»ade  and  it  is  ver>'  pn»l»al»l«' 
th.it  •^nim  «.f  thu'H«'  inten-Med  in  the  matter  may  \h*  able  to  suggt*st  im- 
pri*vi  lilt  iii^  ii)M»n  tlie  apjiaratii^i.  A  eontimious  glass  tulM>  n^Khl  U> 
n-  'i  iM'twirn  thr  riM-rvoir  and  filter  eandle,  thus  eliminating  tme  juint. 
l»iif  It  hii"  In  I  II  thuiiirht  that  the  inerea*<eil  liability  of  breakngi*  n^uulti 
m«>ri-  than  ntT<*et  any  disulvanta^ce.     It  n*ight  also  Im*  {MMsible  to  rnnent 


FACTORS  AFFECTING  THE  PARASITISM  OF  USTILAGO  ZHB 

F.J.     PlEMBIBEL 

Because  certain  facts  seemed  to  indicate  a  different  life  hitttorv  fmm 
that  usually  credited  to  Ustilago  Zea  (Beckm.)  linger.,  on  corn,  field  inocula- 
tion eicperiments  were  carried  on  during  the  summers  of  1913  and  1914. 
The  results  of  the  experiments  were  such  as  to  make  a  more  detailed 
investigation  of  the  spores  and  sporidia  highly  desiraUe. 

The  works  of  Von  Waldcheim  (10),  Brefeld  (2,  3),  Hitchcock  and 
Norton  (6),  and  Clinton  (4)  have  given  us  the  salient  poinis  in  the  life 
hudory  of  this  parasite,  and  numerous  other  investigators  have  niaile 
additional  contributions  from  time  to  time,  showing  that  the  control 
of  the  fungus  is  a  difficult  problem.  The  spores  of  the  smut  are  wi<lely 
distributed  by  the  wind  and  are  produced  in  large  numbers  throughout 
the  growing  season.  They  are  capable  of  germinating  immediately  and, 
in  a  suitable  medium,  they  produce  immense  numbers  of  sporidia  which 
may  bud  in  a  yeast-like  manner  and  produce  a  host  of  others.  The  pro- 
duction of  the  sporidia  in  largd  numbers  in  the  field  is  possible  in  such 
places  as  manure  or  compost  heaps. 

Brefeld  (2)  ccmductini  a  few  expc^riments  from  which  he  concludctl  that 
s|K)ridia  arc  short  livo<l,  d\ing  in  five  weeks  when  dry.  The  sporidia 
thenifore  have  l)cen  chanicterizeil  as  Innng  *Wiort  lived"  and  ver>'  little 
is  really  known  concerning  the  factors  affecting  their  vitality.  Nor  do 
wo  know  the  fate  of  spon's  on  the  com  used  for  ensilage.  The  prrarnt 
inv(^igation  was  made  in  an  effort  to  secure  more  definite  information 
on  thes4*  jMiiiits. 

INOri'LATIO.V    EXPERIMENTS 

Methods 

Pun-  (*ultun:9<  of  tho  fuiif^us  wort*  ohtuimMl  by  the  poured  plate  method, 
u.*(u:illy  on  Ix'^Twort  aK:ir.  Tho  c<)loni«'$i  wen*  later  tranjiferrod  to  agar  in 
tulH*^.  SiM»ri<iia  from  pure  (Miltun*  wrn*  then  used  in  the  inoculaticin 
ex(NTiiiii*iits.  IiiociihitionH  wt'n*  ni:ui«'  either  by  smearing  thi*  sporidia 
din-rtly  on  in  tin*  plant  parts  or  by  |>la('inK  th«>m  in  water  and  applying 
\\i\>  ^u^^M•Il•^if^n  of  >|H>riiiia  by  inrans  of  ji  dn>p|H*r  or  hypodemiic  s\Tingiv 
'rh«*  hypiMit-niiic  >yrin^('  w:i>  umsI  when  it  was  d4*sin*d  to  incKruIato  the 
vvrv  voiinK  part>  which  had  not  v«*t  Ut^n  unfolded. 


1917]  Piebieisel:  Parasitism  of  Ustilago  Zisim  295 

Spores  were  ako  used  in  inoculating  the  plants — ^usually  they  were  dusted 
directly  into  the  tops  of  the  plants  or  mixed  with  moist  soil  and  then 
applied.     In  a  few  cases  the  spores  were  applied  in  suspension  in  water. 

Factors  affecting  infection 

During  the  summers  of  1913  and  1914  a  total  of  2064  plants  of  Minne- 
sota no.  13  com  were  inoculated.  In  all  eighty  different  series  of  plants 
were  used  in  the  tests.  The  highest  percentage  of  infection  in  any  series 
in  the  summer  of  1913  was  70.8  and  in  the  summer  of  1914,  84.2.  These 
results  were  obtained  by  injecting  suspensions  of  sporidia  in  water  into 
the  growing  point  or  as  near  it  as  possible. 

Experiments  were  made  to  determine  the  effect  of  the  following  factors 
on  the  success  of  infection:  age  of  the  plants;  injury  to  plants;  age  of  the 
spores  and  sporidia.  Observations  were  also  made  on  the  relation  of 
early  planting  close  planting  and  soil  conditions  to  the  amount  of  smut 
present  in  tha  fields. 

Age  of  the  plants.  It  was  found  that  successful  infection  depended  very 
largely  on  the  age  of  the  plants  or  plant  parts  inoculated.  Healthy, 
vigorous  plants  about  2  to  3  feet  high  are  most  susceptible.  It  was  very 
diflBcult  to  infect  very  yoimg  or  very  old  plants.  These  results  confirm 
those  obtained  by  Brefeld  (3)  and  Hitchcock  and  Norton  (6). 

Injury  of  the  plants.  Experiments  performed  by  Chnton  (4)  showed 
that  mutilation  of  the  com  plants  when  about  ready  to  tassel  tends  to 
increase  their  susceptibiUty.  The  experiments  of  the  writer  Ukewise 
showed  that  injury  tends  to  increase  the  chances  for  infection.  When 
young  leaves  were  injured  and  then  inoculated,  the  resulting  infection 
usually  spread  from  the  point  of  injury  as  a  center.  Many  of  the  infected 
leaf  areas,  however,  never  developed  sufficiently  to  produce  mature  spores. 
This  was  probably  due  for  the  most  part  to  the  rapid  maturing  of  the  leaf 
tissues  and  the  consequent  inability  of  the  fimgus  to  spread  through  these 
older  tissues.     Injury  is  not  necessary,  however,  for  successful  infection. 

Age  of  the  spores  and  sporidia.  The  length  of  time  that  the  spores  can 
withstand  unfavorable  conditions  is  important  from  the  standpoint  of 
the  propagation  of  any  fimgus.  Brefeld  (2)  demonstrated  that  corn  smut 
spores,  eight  years  old,  germinated,  but  he  did  not  attempt  to  secure 
infection  with  them.  The  writer  obtained  spores,  five  years  old,  and  made 
field  inoculations  with  them  by  dusting  into  the  tops  of  the  plants.  Six 
per  cent  of  the  inoculated  plants  became  smutted  near  the  point  of  inocula- 
tion. Two  per  cent  of  smut  also  appeared  in  the  check  plot  but  the 
infected  areas  appeared  on  various  parts  of  the  plants. 

Many  fimgi  when  kept  in  continuous  culture  on  nutrient  media  for 


296  Phytopathology  [Vol.  7 

some  time  lone  their  power  to  infect.  Brefeld  (2)  found  that  amut  siporidia. 
when  kept  for  a  year  in  continuous  culture  in  liquid  media,  Iok(  their 
viability.  The-  writer  kept  the  sporidia  in  continuous  culture  on  lienr- 
wort  agar  for  eight  months.  The  culture  tubes  containing  the  sporidia 
were  then  buried  in  snow  out  of  doors  where  they  remained  for  a  month. 
Inoculations  wore  then  made  in  the  greenhouse  on  two  com  plants.  (>no. 
a  snuill  plant  about  2  feet  high,  became  infected  in  each  of  the  five  leaves 
inoculated.  The  other,  about  5  feet  high,  was  inoculated  on  an  ear  and 
prcxluced  a  large  smut  Imil.  Thus  it  will  Ik^  seen  that  continuous  culture 
of  the  sporidia  on  a  solid  nutrient  medium  for  a  period  of  eight  month<«, 
followed  by  freezing  for  a  month,  did  not  destroy  their  ability  to  infen. 
Recently,  portions  of  a  pure  cultiuv,  that  had  Ihwu  maintaine<l  on  l>eer- 
wort  agar  sinct^  June,  1913,  a  period  of  three*  and  one-half  years,  were  placiNl 
in  hanging  drops  of  di.slill(Hi  water  and  also  of  mo<Iifie<l  (  ohn*s  s4>lution. 
In  th<»se  cultures  individual  sporidia  wen*  probably  no  longer  present  but 
theR*  was  a  miiss  of  short  hyphal  thremls,  apparently  resting  segments 
of  th<*  g<Tin-tulH^s  of  the  sporidia.  The  ends  of  thes<*  hyphal  thn'iMls  were 
deiiw»ly  pn)t()j)l:ihmic  and  wlM»n  they  wen*  pUice<l  in  water,  or,  l>ett4*r 
still,  in  a  li(]uid  nutrient  me<liuiii  they  again  pnNiu<*iHl  sporidia  by  budding. 
Tlu^M^  sporidia  continucni  to  bud  until  the  supply  of  nutrient  matf^rial  wan 
ex)iaust(Ml  when  they  again  sent  out  long  thin  g<*rm-tul>es.  The  writer 
inoculated  four  plants  with  some  of  the  pure-i*ultun*  material  but  has  not 
as  yet  succ<h'(Um1  in  securing  successful  inftnrtion. 

Kjftct  of  varly  planting ^  char  planting  and  soil  conditions,  Arthur  and 
Stuart  (1)  n*iM)rt  that  early  planting,  close  planting  and  moist  rich  M>il 
incn*ji^e  the  ani(»unt  of  .snnit.  Il^iiny  periods  were  also  closely  followeil 
by  outbn*aks  of  snuit  in  the  com  fields.  The  following  obser\*ations 
niadt*  by  the  writer  point  to  similar  condusioiLs. 

The  corn  us<sl  for  the  inocuLition  ex|H*riments  was  planted  at  succeMtive 
intervals  throughout  the  s<*ti.son  .so  as  to  have  at  all  times  an  abundance 
of  i)lant.s  in  the  sus(*eptiblc  stage.  The  plots  wen*  carefully  examined  for 
smut  and  it  was  found  that  a  gn^ater  amount  of  smut  was  present  in  the 
plots  planird  carlitT  in  the  M»2ison.  The  phuits  in  such  fiehls  are  in  tlu* 
ni«»>t  .suMTptible  condition  at  a  time  when  the  weather  Ls  still  fairly  cool 
and  iMoiM  ami  the  coiiditinns  for  infection  ver\'  favorable.  The  later 
summer  weather  'i>  likelv  to  In*  t<M»hot  a n<i  t<N)drv  for  successful  infection. 
I  >:ite  Mill  in  let  with  its  I  lion*  frequent  rains  and  c<N>ler  weather  again  bring!« 
on  a  fre.sh  <iut)>reak  of  smut,  the  parts  most  aflf(*ct«sl  lN*ing themdinientar>' 
ears,  siiin*  tin?  n*st  «»f  the  plant  is  aln*aily  t-o<»  matun*. 

W  htii  rtirii  i>  L!ri»\\ii  in  (*ln.s('ly  plantiMi  n»ws  for  gH*en  fodder  or  silagp 
purpo-i-.  till-  >inut  i>  aUu  nmn*  pn*valent.  probably  l>eeause  the  Mini  in 
such  tirlils  n'Miaiii**  Mirruli'ut   fur  a  longer  iteritNi  of  time.     In  one  such 


1917]  Piemeisel:  Parasitism  of  Ustilago  Zea  297 

field  which  had  been  continuously  cropped  to  com  a  number  of  years, 
there  was  25  per  cent  of  smut  as  compared  with  7  per  cent  in  neighboring 
fields  where  the  com  was  3  to  4  feet  distant  in  the  rows  and  on  which 
rotation  had  been  practiced.  Com  on  poorly  drained  soils  or  on  those 
which  are  too  dry  has  less  smut  than  that  on  a  rich,  moist  soil.  The 
former  types  of  soils  produce  weak  plants  that  mature  rather  rapidly, 
while  a  moist,  rich  soil  produces  a  very  vigorous  succulent  plant  which 
apparently  is  also  more  susceptible  to  smut.  These  observations  further 
confirm  the  conclusions  of  other  writers. 

Character  of  infection 

Smut  boils  are  often  so  generally  distributed  on  a  plant  as  to  lead  one 
to  suppose  that  the  infection  may  have  occurred  on  yoimg  plants  and  that 
the  fungus  then  spread  throughout  the  growing  tissues.  It  is  not  im- 
common  to  find  a  single  plant  on  which  the  tassel,  leaves  and  the  primary 
and  rudimentary  ears  are  smutted  while  adjacent  plants  are  entirely 
free  of  smut.  It  is  therefore  difficult  to  explain  why  the  successive 
infections  should  all  have  occurred  on  one  plant.  If  the  smut  were  sys- 
temic such  a  phenomenon  would  be  easily  explained.  Brefeld  (3),  how- 
ever, concluded  from  his  inoculations  that  the  infection  is  local. 

Field  observations.  In  order  to  obtain  more*  complete  information  on 
this  point,  the  writer  made  careful  observations  on  plants  artificially 
inoculated  in  the  field.  The  results  showed  that,  when  successful,  signs 
of  infection  always  appear  in  from  ten  to  fourteen  days  after  inoculation 
and  that  the  fimgus  spreads  but  Uttle  in  the  tissues.  On  several  plants 
where  the  inoculum  trickled  down  the  sides  of  the  culm,  smut  boils  were 
produced  at  a  number  of  points  along  the  line,  involving  the  leaves,  the 
primary  ears  and  rudimentary  ears.  In  nature,  similar  conditions  might 
easily  arise  when  a  spore  falls  into  the  water  contained  in  the  funnel  formed 
by  the  unfolding  leaves  and  produces  sporidia.  The  sporidia  could  then 
be  easily  washed  out  to  the  various  parts  of  the  plant  by  rain.  This  is 
especially  probable  since  the  spores  of  the  smut  can  germinate  as  soon  as 
matiu-e  and  parts  beneath  the  point  of  primary  infection  are  particularly 
Uable  to  attack. 

Brefeld  (3)  and  Kiihn  (7)  both  obtained  successful  infection  on  a  few 
seedling  plants  but  in  all  cases  such  plants  were  destroyed  by  the  smut. 
In  order  to  further  ascertain  the  results  of  early  infection,  ten  very  young 
smutted  plants  in  a  fodder-corn  field  were  selected  and  marked.  All  of 
the  plants  were  about  a  foot  high  and  showed  varying  degrees  of  infection. 
Of  the  ten  plants  under  observation  eight  were  killed  by  the  smut  in  less 
than  a  month  and  the  other  two  were  greatly  stunted.    These  two  plants. 


298  Phytopathology  (Vol,  7 

however,  produced  healthy  ears.     Furthennore,  many  plants  that  were 
found  smutted  when  quite  youn^  matured  healthy  ears. 

Greenhouse  inoculations.  It  han  abeady  been  stated  that  in  the  field 
the  infection  of  verj'  young  com  plants  was  ver>'  difficult.  Further  inocula- 
tions were  made  in  the  greenhouse  upon  germinating  seeds.  Forty-three 
seiMllings  were  dipped  into  a  water  suspension  of  sporidia  and  then  planted 
in  pots.  None  of  the  plants  developed  smut  although  they  were  allowed 
to  gnjw  for  one  and  one-half  months.  These  result*  indicate  strongly  that 
infect i(m  is  purely  local  and  not  systemic. 

THK    VITALITY   OF   SPOKKS   A.ND   SI'(»mi)IA 

It  is  a  well-known  fact  that  corn  smut  spon»s  retain  their  viability  for  a 
numlMT  of  y(*ars,  U^ing  ext namely  resistant  to  unfavorable  conditions. 
V<»ry  little,  how(»ver,  is  known  con<*(»nung  the  vitality  of  the  sfMiridia  and 
their  resi.^'tance  to  unfavorable  con<litions  has  hitherto  Ihhmi  supi>oM'<l  to 
Yh"  very  slight.  Th(i  writ(T  al.**o  investigated  the  vitality  of  the  siKin-s  and 
sporidia.  The  cfTcets  of  the*  following  factors  on  the  vitality  of  >|H»n'^ 
wen'  considertMl:  (1)  the  silo,  (2)  t<»mix*ratun»,  (3)  carlnm  dioxiilr. 
(4)  acids,  and  (5)  s4'asonal  factors.  Tlu'  influence  of  the  following  fa<'- 
tors  on  th<'  vitality  <»f  sporidia  w:is  rcmsideriMl:  (1)  tem|MTatun*.  \'2* 
desicration,  {'^)  arids. 

V italHij  of  spares 

Since  a  considerable  amount  of  corn  .^mut  must  1h»  carritMJ  over  into 
silos  with  the  corn  in  the  pnK*ess  of  .silo  filling,  it  is  imiMirtant  to  know  the 
fat"  of  such  spon^s.  T<J  d(»t ermine  this,  si>on's  wenM*olUM't<»<l  inc|uantity 
and  phu'ed  in  several  .silos  for  various  h^igths  of  time.  A  brief  sununar>* 
of  the  n»sults  is  given  Im»Iow. 

Sufuplrs  I.  TIh^si'  siK)n»s,  which  had  just  mature<i,  wen*  iHilhvt***! 
S<^pt4'm)HT  11.  HM4.  eiu'los<Hl  in  a  che<*s(M*loth  bag  and  phuM^I  al»out  on«^ 
third  of  the  way  down  in  a  wtMHien  silo.  A  sample  of  th"  .Nune  lot  w:lh  kept 
a>  a  rheek  in  the  lalM)nitory  at  nM)iii  t«»m|H»nitun*.  Tin*  sj)ore>  utTi' 
n^eovered  from  the  .^^ilo  on  NovemlxT  2,  1914,  after  having  Iki'Ii  th«-r^» 
alM»ut  s«  ven  we<*ks.  T\\r  .^pon's  w<in»  fn)W»n  and  wen»,  then'fon».  thawt^i 
out  gradually  in  the  laboratory. 

Satnph-  II.  TIm^'  s|H)n*s  w«»n'  ('olUvtiMl  and  phu'e*!  in  a  brit*k  >d«» 
S'pleiiilHT  2.  11M4.  The  s|M»n's  wen*  eiielosiMl  in  a  bag  and  plaeeil  alN»ut 
l."»  ii^i'.i  I'rtim  the  lM»ttom  of  th<*  >\\o  and  aUmt  2  fe«*t  fn»in  th«'  M«le.  Thfv 
\\rr«-  reioveHMJ  M:ireli  4,  nu.*>,  aft«T  having  lKM»n  in  the  mIo  for  tivor 
t^ii'iilN-'ix  wei»k.«».  The  s|H)n»s  when  nM'ovenMJ  wen*  frt>z<'n  and  then^fon* 
the  s:iiiipie  wa>  dividt^d  into  thret*  {Mirtions  :i>  follows:     (1)  A  |M»niou 


1917] 


Pibmeisel:  Parasitism  op  Ustilago  Zkm 


299 


was  kept  frozen;  (2)  a  portion  was  kept  moist  at  laboratory  temperature; 
(3)  a  portion  was  air  dried  and  kept  at  laboratory  temperature.  The 
object  was  to  eliminate,  if  possible,  the  method  of  handling  the  spores 
as  a  factor  which  might  influence  their  germination. 

Samples  III  and  IV,  The  spores  were  collected,  placed  in  bags  and 
buried  in  a  silo  October  6,  1915.  Sample  IV  was  placed  about  2  feet 
from  the  side  and  about  8  feet  i^m  the  bottom  of  the  silo.  It  was  re- 
covered January  20,  1916,  and  was  kept  frozen  until  February  8,  1916, 
and  then  kept  dry  at  room  temperature.  Sample  III,  which  had  been 
placed  in  the  center  of  the  silo,  about  two-thirds  of  the  way  up,  was  re- 
covered January  15,  1916.  It  was  also  kept  frozen  until  February  8, 
1916,  when  the  spores  were  gradually  thawed  out  and  then  tested  for 
germination. 

TABLE  1 
Results  of  germination  tests  of  spores  kept  in  silo 


NUMBER 
or  TRIALS 


SPORE  LOT 
TESTED 


MEDIUM   IN  WHICH   TESTS  WERE   MADS 


PERCENTAQB  Or 
OEHMINATION 


Sample  I 


11 

Silo 

Distilled  water 

0 

10 

Check 

Distilled  water 

25 

5 

Silo 

Modified  Cohn's  solution 

0 

5 

Check 

Modified  Cohn's  solution 

90 

6 

Silo 

Tap  water 

0 

5 

Check 

Tap  water 

12.5 

Sample  II 


42 

Silo 

Modified  Cohn's  solution 

0 

14 

Check 

Modified  Cohn's  solution 

90  to  100 

10 

Silo 

Distilled  water 

0 

8 

Check 

Distilled  water 

5  to  15 

5 

Silo 

Tap  water 

0 

5 

Check 

Tap  water 

15 

Samples  III  and  IV 


18 

Silo 

Modified  Cohn's  solution 

0 

Check 

Modified  Cohn's  solution 

95  to  100 

10 

Silo 

Sterilized  distilled  water 

0 

5 

Check    ' 

Sterilized  distilled  water 

75  to  95 

7 

Silo 

Tap  water 

0 

3 

.    Check 

Tap  water 

50  to  75 

Sample  V 


50 
16 


Silo 
Check 


Modified  Cohn's  solution 
Modified  Cohn's  solution 


0* 
75  to  95 


•  One  spore  germinated. 


300  Phytopatholoot  IVol.  7 

Sample  V.  This  sample  was  collected  and  buried  in  a  silo  about  12 
feet  from  the  top  and  2  feet  in  from  the  side  on  October  4,1915.  It  was 
recovered  March  16,  1916,  thawed  out  in  the  laboratory  and  germination 
tests  were  made  immediately.  The  results  of  the  germination  tests  are 
summarized  in  table  1. 

The  table  shows  that  with  but  one  exception  the  smut  spores  did  not 
germinate  after  having  been  in  the  site.  Samples  I  and  II  were  both 
tested  at  the  time  they  were  collected,  when  68  per  cent  and  28  per  cent, 
respectively,  germinated  in  water.  The  single  spore  whidi  germinated 
shows  a  spore  may  occasionally  retain  its  viability  after  ha\ing  been  in 
silage. 

The  death  of  the  spores  may  be  attributed  to  a  number  of  possible 
causes — (1)  unfavorable  temperatures,  (2)  gases  produced  during  the 
changes  in  the  silo,  (3)  the  acids  and  other  chemical  substances  produce<l 
by  fennentation,  (4)  pressure.  The  effect  of  each  of  these  factoni  except 
the  last  was  tried. 

The  effect  of  iemiyerature.  The  exact  changes  which  accompany  the 
fonnatioii  of  silage  from  green  com  arc  but  imperfectly  known.  Esten 
and  MjL»<on  (5),  however,  have  shown  that  silage  fennents  best  l)etwp«en 
75°F.  and  80°?.,  and  that  the  temperature  never  rises  alx>ve  86®F.  in 
profMTly  prtjpanxl  silage,  except  in  the  topmost  layers  where  destructive 
fennentation  occurs.  Noidig  (8)  n*|K)rts  a  nuiximum  temperature  of  91'F. 
Such  toiniKTatures  are  not  in  thi»nist»lves  sufficient  to  kill  com  smut  spores, 
since  Stt»wart  (1>)  foiuid  that  a  teinp(»rature  of  52*'(\,  for  fifteen  minutes 
was  n(*cessar>'  to  kill  tho  siK)rt\s  when  immonHHl  in  water.  He  also  found 
that  expo.Hure  to  dr>'  hoat  In't w(»i»n  lOo.SX'.  an<l  1()G°(\,  for  fifteen  minut4«« 
kille<l  th<5  spores. 

In  a  few  tests  ina<l(*  by  the  writer  some  spon*  withstood  a  dry  heat  of 
103  (\  for  fiv(»  niinut(*s,  hut  tus  a  rule  a  temiwratuns  of  lOO^'C.  for  five 
niinutcs  is  .Kuflici<*nt  to  <U^troy  the  gcnninating  powers  of  the  sfxires. 

Fn't^zing  tcnijM'nitun's  do  not  w<*in  to  injure  the  s|M>rps  as  they  Hur\'ive 
our  .sovurest  wintrrs.  Si>on*s,  ston^l  in  a  sImhI  when*  they  were  nien*Iy 
shclttToii  from  t^now  and  rain  but  were  exposeti  to  all  the  rigors  of  wint4T. 
girnniiiatrd  wrll  in  >pring.  S|H)res  that  were  frozen  for  short  periotLn  i»f 
tinif  and  tlicii  lasted  for  germination  ap|)eanHl  to  have  l)een  Ktimulat4*d 
by  \\\v  viM.  Thr  fxtremcs  in  t(Mn|)eratun^  which  the  spores  cncount4»r 
in  tlir  >iln,  thrn:fnn%  can  have  no  intiuenr^'  on  their  vitality. 

Th»  tjhtt  nj  tjnsrs.  Littfc  IS  known  of  the  gases  produced  in  silage 
formaiinii  altlmuKh  it  i>  not  pmbablo  that  they  would  take  an  active  part 
in  tli<*  ilr.otnK'tinii  of  the  >mut  >|)ort*.*<.  ('arlM»n  dioxide  is  probably  pn>- 
<lii<'«-ii  ill  ^n*:iif>t  ({uaiiiit y  a.-*  a  re>ult  of  the  fermentative  action.  A  single 
exiM-nm«'iit  ux'^  made  to  <iet<*rmiiu!  the  eiTi*i>ts  of  the  gas  on  tlie  sponrs*. 
I)r\'  ^|M>res  wen*  pla('«'d  in  a  bottlu  and  carlnm  dioxide  was  passed  in.     The 


1917]  PiEBfEisEL:  Pabasitism  of  Ustilaqo  Zrs  301 

spores  were  thus  exposed  to  the  gas  for  ten  days,  when  germination  tests 
were  made.  The  spores  were  not  only  imharmed  but  germinated  much 
more  quickly  than  those  of  the  same  lot  which  were  used  as  checks.  At 
the  end  of  two  days  no  difference  was  apparent  in  the  germination  of  the 
two  lots  of  spores. 

The  effects  of  acids.  It  seems  probable  that  the  loss  of  viability  of  spores 
may  be  due  to  the  chemical  substances  produced  in  silage.  Considerable 
quantities  of  acids  are  produced  rapidly ,  the  maximum  amount  of  each 
usually  being  produced  within  two  weeks  after  the  silo  is  filled.  The  total 
acidity  of  silage,  according  to  Esten  and  Mason  (5),  is  about  1.0  per  cent 
to  1.5  per  cent,  the  principal  acids  in  order  of  their  importance  being  lactiCi 
acetic  and  propionic.  In  experiments  to  ascertain  the  effect  of  certain 
of  these  acids  on  the  germination  of  smut  spores  it  was  found  that  a  con- 
centration of  1  per  cent  of  either  acetic  or  lactic  acids  or  a  combination 
of  the  two  was  sufficient  to  inhibit  smut  spore  germination.  However, 
spores  germinated  in  a  diluted  sample  of  normal  silage  juice. 

The  above  results  are  significant  in  that  they  indicate  to  some  extent 
what  happens  to  the  spores  in  the  silo.  The  optimum  for  the  germination 
of  spores  is  reached  at  some  point  in  the  rise  of  temperature  which  accom- 
panies the  formation  of  sUage.  The  germination  of  the  spores  is,  however, 
inhibited  by  the  presence  of  the  acids.  Acetic  acid  penetrates  rapidly 
and  kills  plant  tissues.  Hence,  it  is  not  unlikely  that  the  spores,  which 
are  exposed  to  its  action  for  a  long  time,  are  killed  by  it. 

Seasonal  factors.  Fresh  spores  were  collected  from  time  to  time  and 
observations  made  on  their  germination.  The  first  tests  were  made  in 
the  summer  of  1913  and  fresh  spores  germinated  very  readily  in  water  at 
room  temperatiu^.  The  tests  made  in  the  smnmer  of  1914  were  more 
complete,  begmning  with  the  very  first  smut  spores  produced  in  the  field. 
The  first  germination  test  of  fresh  smut  spores  was  made  Jime  24,  the 
last  test  on  October  10.  Fifteen  distinct  tests  were  made,  the  results 
showing  conclusively  that  fresh  spores  germinate  readily  in  water.  In 
fact,  fresh  spores  germinated  much  better  than  did  spores  from  the  same 
lot  kept  imtil  winter.  The  average  percentage  of  germination  for  the 
entire  series  was  42.8,  the  percentages  in  different  hanging  drops  varying 
from  0  to  85,  a  result  often  obtained  when  water  is  used  as  the  medium 
for  germination.  This  shows  that  spore  germination  in  water  is  some- 
what capricious,  thus  probably  explaining  the  conflicting  r^ults  obtained 
by  various  investigators.  The  germination  in  sugar  solutions  and  liquid 
nutrient  media,  especially  modified  Cohn's  solution  is  more  uniform,  100 
per  cent  of  the  spores  almost  always  germinating.  No  difference  could 
be  foimd  in  the  germination  in  sterilized  distilled  water,  distilled  water, 
tap  water  or  rain  water.  Incubating  the  cells  at  24^C.  to  38"C.  did  not 
seem  to  influence  the  rate  or  amount  of  germination  of  the  smut  spores. 


302  Phytopathology  [Vou  7 

Vitality  of  sparidia 

Methods.  In  the  studies  of  sporidia,  pure  cultures  of  the  smut  were 
used  throughout.  Spores  were  sown  in  poured  plates  of  beenn'ort  nfcmr. 
In  about  two  days  the  .spores  germinated  and  the  position  of  the  colonies 
was  niarke<l.  At  the  end  of  four  or  five  days  when  the  colonies  were 
about  the  size  of  a  pinhead,  they  were  transferred  to  beerwort  agar  slanU. 
A  nunil)er  of  other  nutrient  media  were  also  tried,  \iz.:  carrot  agar, 
nitn)gen  free  agar,  beef  agar,  oat  agar  and  a  synthetic  agar.  Of  these, 
beerwort  agar  was  foimd  to  l>o  the  Ix^,  although  a  good  growth  was  also 
obtaino<l  on  carrot  agar. 

Cultural  characters  and  morphology.  When  the  colonies  first  appear 
th(»y  are  round,  raistMj,  convex,  opaque,  slightly  shiny  to  dull,  light  ctvam 
in  color.  -\s  the  colonies  grow  older,  the  e<lge  Injcomes  somewhat  IoIknI 
and  irregular,  and  the  surface  l)ecomes  convoluUnl,  ridge<l,  or  sharply 
papillaU*.  TIm*  color  (i«^p(»ns  with  age,  lKH*oming  light  lavender  in  uU\ 
cultures.  The  consi.st<»ncy  is  first  soft  and  n)py,  then  Ixvomes  mucibigin- 
ous  or  rublxTv;  or.  when  k<»pt  inoi.Kt,  but\ToiLs. 

TIh»  colonics  consist  of  sjKiritiia  whi<'h  are  abjointed  fnim  the  si<les  and 
(K*casionally  from  the  end  of  the  promyc<»liuin.  These  s|>oridia  are  of 
the  same  iiatun^  iis  those  produ(*cd  l)eneath  the  surface  in  liquid  nie<tia. 
The  sporidia  pro<iu<*cMl  in  the  air  from  a  liquid  culturo  are  small,  sharply 
fusoid  and  fairly  thick  wuIUmI.  Th<\v  are  pnnluced  in  long  cliains.  Thosie 
produceii  within  the  li(iiiid  or  on  solid  nutrient  mo<lia  are  larger  tlian  the 
air  cronidia,  not  as  thick  walU^l  luid  aro  somewhat  roumled  at  the  endf. 
They  are  pluin|KT,  <*ontaiii  mon'  oil  globuk*s  and  are  not  priNluceil  in 
such  long  cliains.  The  walls  an^  a[>pan'ntly  somewhat  nmcilaginoua. 
In  continuous  cultiux)  the  s|K>ridia  pnKiuce  hmg  gorm-tubcs,  the  emb  of 
which  an^  dens4»ly  i>rotophismic  and  which,  therefore,  can  become  nvttng 
si'gnicnts  |H)ssessing  all  the  pn)|K'rties  of  sporidia.  The  gemi-tulNy  Imv 
come  much  cntangl(*d  and  give  the  cultun^  its  rublM*r>'  consistency, wink* 
the  disintegration  of  the  empty  portions  of  the  hyphae  give  it  its  muci- 
laginous chara(*ter.  \  smear  from  such  a  culturo  dries  almost  instantly 
and  b<*<>onu^  brittle.  While  s|>oridia  pro<luccil  in  culture  may  not  In* 
exju'tly  like  thos4*  pnMiu(*ed  in  nature,  still  they  must  Iw  ver>'  similar  to 
thos4*  which  we  iniiigine  an*  phnIucihI  in  such  great  abundance  in  manure. 

Thrrmal  rtlatitmfi.  A  cf)mi)lete  understanding  of  the  tliemial  relatione 
of  com  sinut  >|M»ridi:i  would  not  only  \n*  of  value  in  throwing  additional 
light  upon  the  phenomena  (»f  inf(*<'tion,  but  it  would  also  show  more  clearly 
the  nptitiiiun  conditions  for  the  profmgation  of  the  fungus.  An  attt^mpt 
wa-*  thenfon*  in.ide  to  as<*ert.ain  the  minimum,  maximum  and  optimum 
t4-niiMr:itun*>.     Both  tlried  and  actively  vegt;t4iting  s|)oridia  were  tested. 

At  tem|N*ratun*s  nmging  from  2i) C  (o  2rr(\  the  aniall  sporidia  bud 


1917] 


Piemeisel:  Parasitism  of  Ustilago  Z^jr 


303 


profusely  in' nutrient  solutions.  As  the  temperature  is  increased  to  above 
26®C.  the  sporidia  show  a  greater  tendency  to  produce  long,  slender  germ- 
tubes.  At  35°C.  growth  is  somewhat  inhibited  and  the  cells  begin  to 
show  an  increase  in  the  number  of  vacuoles.  Increasing  vacuolation 
continues  with  a  rise  in  temperature  to  40°C.  where  growth  practically 
ceases,  while  at  46*^0.  the  cells  are  no  longer  alive. 

Attempts  to  determine  the  lowest  temperature  which  the  sporidia  in 
liquids  or  on  solid  nutrient  media  can  endure  gave  negative  results  be- 
cause they  withstood  the  severest  cold  of  the  winter  (about  —  28®C.). 
Alternate  freezing  and  thawing,  however,  kills  moist  sporidia.  Desic- 
cated sporidia,  on  the  other  hand,  were  not  only  able  to  withstand  severe 
freezing  but  in  some  cases  were  not  severely  injured  by  alternate  freezing 
and  thawing. 

When  exposed  to  alternate  freezing  and  thawing,  however,  there  seems 
to  be  some  injury,  as  no  subsequent  growth  occurred  in  two  out  of  three 
tests.  Smears  direct  from  pure  cultures  were  not  killed  by  drying  for 
one  day  at  21°C.  or  for  fourteen  days  at  a  temperature  of  from  7®  to  9°C. 

TABLE  2 

The  effect  of  .temperature  on  desiccated  sporidia  of  Ustilago  Zece,    AU  sporidia 

dried  at  tl^'C. 


TBBT 

Km- 

BBB 

KUM- 

BBBOF 
TBIALB 

NUBf- 
BBBOF 

DATB 
DBIBD 

TBMPBBATUBX  TO 
WHICH   BXPOSED 

TIMB 
BXP08BD 

MEDITJM  FOB  OEBMXMATION 

BULTB* 

1 

1 

1 

-IC^C.  to  -7** 

14  days 

Sterilized  distilled  water 

+ 

2 

1 

5 

43** 

15  min. 

Sterilized  distilled  water 

+ 

.     3 

1 

6 

Alternate  freez- 
ing and  thaw- 

31 days 

2  per  cent  sugar  solution 

^— 

4 

1 

7 

ing 
-2*»C.  to  3** 

12hr8. 

Sterilized  distilled  water 

+ 

5 

1 

12 

45'* 

15  min. 

Sterilized  distilled  water 

+ 

6 

1 

16 

28.6^0.  to  3r 

24hr8. 

Sterilized  distilled  water 

+ 

7 

2 

16 

-7 

12hrs. 

Sterilized  distilled  water 

+ 

8 

1 

18 

54^C.  to  55^ 

15  min. 

Sterilized  distilled  water 

— 

9 

1 

19 

40^C.  to  50« 

16  hrs. 

Sterilized  distilled  water 

^ 

10 

1 

20 

-5^C.  to  r  al- 
ternate  freez- 
ing and  thaw- 

12 da3rs 

Sterilized  distilled  water 

+ 

11 

1 

20 

ing 
-5C^.  to  1*  al- 
ternate  freez- 
ing and  thaw- 

12da3rs 

Sterilized  distilled  water 

— 

12 

1 

20 

ing 
28. 5*^0.  toSr 

24  hrs. 

Sterilized  distilled  water 

- 

•  No  growth  — ;  grew  weakly  ^  ;  grew  -f. 


304 


Phttopatholoot 


[Vol.  7 


But  Bporidia  dried  six  days  and  then  exposed  to  alternate  freering  and 
thawing  for  thirty-one  days  were  killed. 

Sporidial  ameara  direct  on  glaas  ooverndipe  from  the  pure  culture  were 
unaffected  by  drying  for  sixteen  days  at  21"^.  and  then  at  28 JS""  to  Sl'X:. 
for  one  day.  Sporidia  first  placed  in  water,  then  dried  for  twenty  dajrs, 
also  withstood  the  same  temperature.  Sporidia  in  smean  were  not  killed 
by  exposure  to  frotn  40^  to  50^C.  for  sixteen  hours,  after  drsring  for  nine^ 
teen  days,  but  appeared  to  be  killed  at  54^  to  55^^  for  fifteen  minutes, 

TABLE  I 
The  effect  of  denceatxon  on  the  tntality  of  eporidia  of  Uetilago  Zem.    AU  te*U  for  ger» 

mination  made  al  il*C. 


• 

a 

i 

1 

p 

2 

MKTBOD  or  FBBrAKATlOir 

KUMBBa  or  DATS  DBIBD 

MBDtm  vmM9  worn         ,    f 

I' 

I 

i 

1 

Grown  in  cells  in  HtO 

3 

Sterilised      distilled  1 

2  days.    Slip  dried 

water 

2 

3 

Spores  germinating  in 
H,0  in  cell.        Slip 
dried 

3 

Sterilised      distilled      ^ 
water 

3 

5 

In  11,0  in  cells.     Slip 

1 

Sterilised  distilled     !  + 

dried 

water 

4 

1 

Smears  made  on  slips 

12 

2  per  cent  sugar  tolu* 
tion 

+ 

4 

1 

Smears  made  on  slips 

50 

Modified  Cohn's  so-     ^ 
lution                        1 

4 

1 

Smears  made  on  slips 

G  at  21*C.  31  at  al- 
ternate     f  reeling 
and  thawing 

2  per  cent  sugar  so-  -   — 
lution 

i 

5 

1 

In  watvr  on  slips 

12 

2  per  cent  sugar  so-      -r 
lution 

5 

2 

In  water  on  slips 

48 

Modified  Cohn*8  so-      - 
lution 

5 

I 

In  water  on  slips 

20  at  21 T. 

24  hrs.  at  2H  5*-3rC. 

Sterilised     distilled   1  * 
water 

() 

1 

»Snenrs  on  slips 

•* 

2  per  cent  sugar  so*      + 
lution 

A 

1 

SiiirnrH  <in  slips 

iA 

Modified  Cohn's  so-      -^^ 
lution 

1 

1 

Siiifiirs  on  slipH 

1  ir,  lit  2r(\ 

Sterilised     distilled      -^^ 

1 

'2\  hrs.  at  2S  5*  31*(\ 

water                         j 

' ,  1 

1 

Siiictrs  (»n  Hlipf« 

'   1  liny  lit  2l*('. 

Sterilised      distilled     ^ 

11  diiys  at    15»-2()t:. 

water                       j 

s     :» 

In  W!it4'r  on  nlipn 

124 

Mo<iifird  CofiD's  so-  '  - 

lution                       \ 

ilmiiicH  vrry  :tl>iin(iant  grrniination;  +  abundant;  ^  sparse:  —  no  gsniii< 


nation. 


1917] 


Piemeisel:  Parasitism  of  Ustilago  Zea 


305 


TABLE  4 


Viability  of  sporidia  of  Ustilago  ZecB  when  smeared  on  a  cover  slip  and  desiccated 
in  light  and  darkness.  All  germination  tests  made  in  sterilized  distilled  water  at 
a  temperature  of  Hl^C, 


» 
NVMBKB  or  TRIAlJB 

• 

•        CONDinOK  XTNDSB 
WHICH  DBISD 

DATS  DRTSD 

BBtnXAS 

2 

Tiight 

1 

+ 

2 

Dark 

1 

+ 

light 

u 

+ 

Dark 

IJ 

+ 

Light 

6 

+ 

Dark 

6 

+ 

light 

8 

+ 

Dark 

8 

+ 

light 

11 

+ 

Dark 

86 

+ 

Light 

87 

+ 

Dark 

149 

+ 

after  drying  for  eighteen  days.  The  thermal  death  point  of  dried  sporidia 
is,  therefore,  probably  about  54®  or  55°C. 

Moisture  relaiions.  In  most  cases  the  sporidia  were  taken  directly 
from  the  pure  cultures  on  beerwort  agar  and  smeared  on  sterilized  cover- 
slips.  The  sUps  were  then  placed  in  steriUzed  petri  dishes  and  were 
allowed  to  dry  at  room  temperature  for  various  lengths  of  time.  In 
other  cases  a  water  suspension  was  first  made  of  the  sporidia  and  drops  of 
this  were  then  transferred  to  the  slips  and  allowed  to  dry  as  above.  When 
the  germination  test  was  made  a  drop  of  the  desired  medium  was  added 
and  the  slips  were  then  moimted  on  Ward  or  Van  Tieghem  cells. 

From  the  results  shown  in  tables  3  and  4  it  is  apparent  that  sporidia 
can  withstand  long  periods  of  drying  without  serious  injury.  Sporidia 
when  taken  directly  from  pure  cultures  withstood  drying  for  149  days  at 
room  temperatiu^.  Not  all  of  these  sporidia,  however,  remained  viable. 
Sporidia  first  placed  in  water  and  then  dried  seemed  to  be  less  resistant  to 
desiccation.  Sporidia  thus  treated  grew  after  drying  for  twenty  days, 
but  not  when  dried  for  forty-eight  days.  The  latter  result  may  be  some- 
what misleading  as  the  number  of  sporidia  in  a  water  drop  is  much  smaller 
than  the  number  in  a  smear  from  pure  culture. 

There  was  no  noticeable  difference  between  sporidial  smears  dried  in  the 
dark  and  in  the  light.  Light,  therefore,  ib  probably  not  very  injurious  to 
sporidia. 

The  above  results  are  not  in  accord  with  those  of  Brefeld  (3)  who  found 
that  sporidia  were  killed  when  dried  five  weeks.  Nor  are  they  in  accord 
with  the  statements  of  Arthur  and  Stuart  (1)  who  characterize  the  sporidia 


306  Phytopathology  [Vol.  7 

88  ''short  lived"  and  further  add,  "These  are  borne  through  the  air  m*hich 
must  be  rather  moist  or  the  aporidia  will  be  killed  by  drying/' 

Chemical  reUUions.  Sporidia  were  placed  in  various  solutions  of  arettc 
and  lactic  acid,  in  com  silage  juice,  and  in  a  mixture  of  various  acids  in 
such  proportion  as  to  approximate  the  composition  of  silage  juice.  If  com 
smut  spores  germinate  when  placed  in  a  silo,  it  was  thought  that  by  mean^ 
of  tests  with  various  acids  commonly  produced  in  silage  the  fate  of  the 
sporidia  might  be  determined.  The  sporidia  in  each  case  were  obtained 
directly  from  pure  cultures  on  beerwort  agar  and  were  transferred  to  the 
solution  from  which  hanging  drops  were  then  made. 

Sporidia  apparently  c^n  grow  in  1  per  cent  acetic  or  lactic  acid  solutions 
or  in  a  mixture  of  the  two.  In  the  lactic  acid  the  sporidia  tend  to  pri>- 
duce  a  greater  numl>er  of  gcrm-tulxw  which  probably  indicates  that  the 
medium  is  slightly  unfavonible  for  gn»i'th.  The  sporidia  also  grow  mrll 
in  expn*sKO(l  silage  juice.  It  seems  probable,  therefore,  that  if  spore?!  do 
gonninate  in  the  silo,  the  sporidia  may  continue  to  live  in  the  silo  for  some 
time.  \Vhothc»r  long  oxposiutj  to  the  action  of  the  acids  would  ln»  detri- 
mental or  not  was  not  detenninoil. 

A  more  concentrated  mixture  of  acids  such  as  was  u.^e<l  in  the  silaite 
acid  U^t  proYtnl  to  l>e  deleterioiw  to  the  growth  of  the  sporidia.  The 
sporidia  appeariMl  starve<l  and  l)ecame  greatly  vacuolate^!,  a  comlition 
which  probably  pnMMHJes  their  death.  The  results  here  obtaineii  are 
not  in  a<'cor<l  with  those  obtained  when  silage  juices  itholf  m'as  usetl, 
possibly  owing  to  the  lack  of  sugars  or  other  nutrients  in  the  silage  acid 
mixtun).  The  efTect  of  the  traces  of  but>Tic  ami  propionic  acids  alone 
upon  the  .sporidia  hjus  not  yet  Ikh^u  determined. 

SUMMARY 

1.  Th<»  inf<*ctinn  of  com  by  ('stilago  Zecr  (Beckm.)  Unger  is  purely 
IcM'al;  no  cvidontM;  of  sv.^teinic  info<*tion  was  obtained. 

2.  Whrn  very  young  plants  Ikn'oiuo  inftK^twl  they  are  often  killed. 

'^.  Injury  to  x\\i*  host  plant.  clos4»  planting,  ver>'  early  or  ver>'  late 
planting,  and  gn»wtli  on  rich  soil  ixxv  con<iucive  to  heavy  smut  attacks. 

•I.  ViKonnisly  gn)wing  plants,  Uitwwn  two  and  three  feet  high,  ar^* 
moM  .»<n.MTptil)U'  tc»  .smut  attack. 

/).  TImj  >j>nn'>  of  !'.  Znr  can  <*au.si»  infe<*tion  either  when  young  or  ohi. 
SiH»n*.s  ^t-nniiKitf'  readily  a.s  simhi  :ls  matun^  and  n*tain  their  viability  fur 
!*cvrr;il  y«':ir>:  infiMiion  wa.s  o)»taincd  by  inoculating  com  plants  with 
sjHin"*  fivf  v<*;ir>  old. 

«i.  riif  rorn->!nur  fuiigiL>  d<M»s  not  los4'  its  vinilcncv  quickly  mhen 
grown  Oh  aii.iticial   ni(»li:i. 

7.  Thi'  .'-pon*'*  of  r.  Znr.  alnntst  without  exception,  lost  their  viabiUty 
after  having  In^i-n  kopt  in  a  silo  f<ir  a  few  weeks. 


1917]  Piemeisel:  Parasitism  of  Ustilago  Ziue  307 

8.  The  factors  causing  spores  to  lose  their  viability  in  the  silo  have 
not  been  determined  definitely;  it  seems  probable  that  the  silage  acids, 
especially  acetic,  may  be  the  destructive  agents. 

9.  Sporidia  were  kept  in  pure  culture  continuously  for  three  and  a  half 
years,  at  the  end  of  which  they  remained  viable.  Inoculation  experiments 
with  the  same  material  gave  inconclusive  results. 

10.  Sporidia  were  desiccated  for  about  five  months  without  seriously 
impairing  their  vitality. 

11.  Freezing  injures  sporidia  but  little;  alternate  freezing  and  thawing, 
however,  is  injurious  to  moist  sporidia,  less  so  to  desiccated  sporidia. 

12.  The  optimum  temperature  for  the  budding  of  sporidia  is  between 
20°  and  26°C.,  the  maximum  at  about  40°C.  and  the  thermal  death  point 
near  46°C. 

13.  Sporidia  can  germinate  and  bud  in  silage  juice,  but  are  injured  in  a 
solution  containing  acids  in  the  proportionate  concentration  in  which 
they  occur  in  silage. 

14.  The  ability  of  sporidia,  as  well  as  spores,  to  withstand  unfavorable 
conditions  is  very  significant  in  explaining  some  of  the  facts  in  the  parasit- 
ism of  U.  Zece, 

Agricultural  Experiment  Station 
University  of  Minnesota 

literature  cited 

(1)  Arthur,  J.  C.  and  Stuart,  Wm.    Corn  smut.    Ind.  Agr.  Exp.  Sta.    Kept. 

12:  84-135.    1900. 

(2)  Brefeld,  Oscar.    Hotanische  Untersuchungen  tiber  Hefenpilze.     Die  Brand- 

pilze  I,  Heft.  6:  67-75.     1883. 

(3)  Brefeld,  Oscar.  Untersuchungen  aus  dem  Gesammtgebietc  der  Mykologie. 

Die  Brandpilze  II.    Heft  XI:  52-92.     1895. 

(4)  Clinton,  G.  P.    Smut  of  Indian  corn  and  teosinte.     Illinois  Agr.  Exp.  Sta. 

Bui.  57.     1900. 

(5)  EsTEN,  W.  M.  AND  Mason,  Christie,  J.    Silage  fermentation.    Conn.  (Storrs) 

Agr.  Exp.  Sta.  Bui.  70.     1912. 

(6)  Hitchcock,  A.  S.  and  Norton,  J.  B.  S.    Corn  smut.  Kans.  Agr.  Exp.  Sta.  Bui. 

62.     189G. 

(7)  KtjHN,  J.    Uebcr  die  Entwickelungsformen  des  Getreidebrandes  und  die  Art 

des  Eindringens  der  Keimfaden  in  die  Nahrpflanze.     Bot.  Zeit.  32: 121-124. 
1874. 

(8)  Neidig,  Ray  E.    Chemical  changes  during  silage  germentation.    Iowa    Agr. 

Exp.  Sta.  Research  Bui.  16.     1914. 

(9)  Stewart,  F.  C.    Effects  of  heat  upon  the  germination  of  corn  and  smut.     Proc. 

Iowa  Acad.  Sci.  6:  2:  174-178.     1895. 
(10)  Waldheim,  Fischer  von.     Ustilaginea.    Jahrb.  Wiss.  Bot.  7,  pt.1-2.     1869. 


SCLEROTIUM  BATATICOLA 
The  Cause  of  a  Fruit-Rot  or  Peppers 

William  H.  Martin 

During  the  pasKt  few  years  the  writer's  attention  has  been  called  a  number 
of  times  to  a  rot  of  ])epper8.  Specimens  were  sent  in  from  various  sections 
of  New  Jersey  witli  iniiuiries  as  to  the  nature  of  the  trouble.  Except  for 
a  drying  and  shrivelling  of  the  epidermis  in  the  more  advanced  stages^,  there 
was  little  extenial  evidence  of  the  presence  of  the  disease.  (>n  breaking 
the  fruit  o|x>n,  however,  the  interior  was  found  to  contain  numen>u8, 
snudl,  l)lack  sdcTotia  which  were  also  present  on  the  seeil.  Isolations 
were  made,  and  in  all  cases  pure  cultures  of  an  organism  resembling 
Sclerotium  Ixitaticola  Taub.  w:u*  securt^I.  The  marked  similaritv  of  the 
two  organisms  hsl  to  exiKTiments  to  establisli  their  pathogenicity  as  m*ell 
as  to  determine  if  the>'  wen*  identical. 

The  fungus  was  isolaltnl  by  :iseptically  breaking  the  diseasetl  fruit;  biin 
of  tissue  were  i\un\  pi<*k<»d  out  with  a  steriliztnl  nee<ile  and  transfernsl  to 
a  pounnl  plate  of  nutrii^nt  agar.  In  most  cas<»s  pure  cultures  wen*  mIk 
taiiied  at  tlie  first  planting.  Inoculations  were  nuule  as  follows:  Healthy 
p<*p{MT  fruits  were  inimerscHl  for  ten  minut(*s  in  a  1  to  1000  s<»lution  <if 
mercuric*  chl(»rid,  w:i>hed  in  sterilized,  distilkni  water  and  place<l  in  a  st<*r- 
ilized  moist  rhamlKT.  .\ttempts  to  pnxluce  the  disease  by  placing  bits 
of  the  rultun*  iiiodia  together  with  sderotia  <m  the  unbn>ken  surface 
failed.  Whitr  tufts  of  mycelium  were  fornuHi  but  the  fungus  Mvmed 
unabh*  to  |M'nrtrat(*  the  ei)idermis.  However,  inoculations  on  a  cut  >ur- 
faci-  iii:id(*  with  a  fiaiiuMl  sralfN^  were  uniformly  successful.  A  larg<*  num- 
Ut  of  iikoculatioiiv  were  nuule  in  this  manner  and  100  p(*r  cent  inftN-tiim 
rr^ultrd.  liifrrtioii  was  rvideiit  in  fmm  four  to  si»ven  days.  Tho  rpi- 
d«Tini>  at  thr  point  of  inflection  Urame  blackemni  and  the  n>t  >pn*aii 
throimhoiit  the  intiTinr.  AftiT  thr  fungus  I NH*ame established,  its  pnign-sv 
wa>  rat  I  If  T  r:ij>id;  in  twn  \V!t'k>  the  t»ntire  interior  of  the  fruits  wen*  in- 
vailnl  ah<l  nunirnniN  Mlrn»tia  d«'velo|H»4l  in  the  tissue  and  on  tin*  m^**!. 
K\rr]»T  lot  :i  M:irkt*ning  of  tin*  I'pidiTmis  there  wen*  no  external  signs  to 
in<li«-:itt'  iltf  |>ir^iii(-«>  of  thr  di><'a>r.  Inoculations  wen*  also  nuuk*  <in 
Iniii  -nil  aTt:ii  h««i  tn  thr  pliint  and  in  evrr>*  c:iS4»  the  n*sultii  were  |Mte^itive. 

.\    •  iiip:>  ut-rr  ni.'nir  t<>  innnilatr  thr  roots  ant  I  stems  of  growing  plant>. 
The  Mill  \\:i>  rari'fullv  rrni<iv<>tl  from  around  the  roots  and  an  incbtion  was 


1917] 


Martin:  Fruit-Rot  op  Peppers 


309 


made  with  a  sterilize^  scalpel  and  sclerotia  from  young  cnlturee  were  in- 
serted. The  soil  was  then  replaced.  Roots  similarly  treated,  but  not 
inoculated,  were  used  as  checks.  Stems  were  likewise  inoculated  and  the 
cut  surfaces  were  wrapped  with  cotton.  On  the  stems  and  roots  the  inocu- 
lations were  not  as  successful  as  on  the  fruits.  Where  infection  did  occur 
the  fimgus  was  found  just  beneath  the  epidermis  or  in  the  pith.  Death 
of  the  plant  or  plant  part  resulted  before  the  mycelium  had  advanced  far 
from  the  point  of  inoculation. 

Reisolations  were  made  from  both  the  fruit  and  stem  and  the  fimgus 
was  again  grown  in  pure  culture.  Inoculations  with  these  reisolated  cul- 
tures were,  in  every  case,  successful. 

During  the  process  of  the  above  inoculations,  similar  inoculations  were 
made  on  peppers  with  cultures  of  S.  bataticola  Taub.  isolated  from  the 
sweet  potato.  In  every  instance  they  were  successful.  Not  only  was 
this  true  but  the  characteristics  and  growth  of  the  organism  were,  in  all 
respects,  like  the  pepper  Sclerotium. 

In  order  to  more  fully  prove  the  identity  of  these  two  pathogenes,  the 
following  comparisons  were  made:  (1)  Growth  on  culture  media,  (2)  cross- 
inoculations  on  sweet  potato  and  pepper  as  well  as  other  hosts,  (3)  develop- 
ment, measurements  and  the  external  and  internal  appearance  of  scleS^rotia. 

Growth  comparisons  were  made  on  com  meal  agar,  potato  agar,  bean 
plugs  and  nutrient  agar.  Abimdant  growth  was  made  and  no  differences 
were  observed. 

For  the  cross-inoculations  three  strains  of  the  organism  were  used. 
One  was  isolated  from  the  sweet  potato,  another,  secured  from  Dr.  J.  J. 
Taubenhaus,  was  likewise  isolated  from  the  sweet  potato.  The  third  was 
isolated  from  peppers.  These  cultures  may  be  designated  1,  2,  3,  respec- 
tively. The  methods  employed  in  the  inoculations  were  the  same  as  have 
been  previously  described.    The  following  inoculations  were  made: 

TABLE  1 
ReaiUts  of  inoculations  on  varioita  hosts  with  three  strains  of  Sclerotium  haiaticola 


HOST 


Sweet  potato  (Ipomoea  batatas) 

Pepper  (Capsicum  annuum) 

Tomato  (Lycopersicum  esculentum) 

Cucumber  (Cucumis  sativus) 

Apple  (Pyrus  malus) 

Eggplant  (Solanum  melongena) 

Turnip  (Brassica  campestris) 

Red  beet  (Beta  vulgaris) 

Parsnip  (Pastinaca  sativa) 

Carrot  (Daucus  carota) 


NUMBBB 

INOCULATBD 

NUMBBB  or 

PXB  CBNT 

WITH  BACH 

CHECKS 

INTBCTION 

CULTUBB 

25 

10 

100 

25 

10 

100 

3 

2 

100 

3 

2 

100 

3 

2 

100 

1 

1 

100 

3 

2 

100 

3 

2 

0 

3 

2 

0 

3 

2 

0 

310  Phytopathology  (Vol.  7 

In  those  cases  where  the  inoculations  were  successful,  no  differennv  in 
gro^^iih  of  the  organism  were  evident.  The  time  before  infection  is  e\-i- 
dent,  varies,  however,  with  different  host  plants.  On  pepper,  cucuiuImt 
and  tomato  from  four  to  seven  da>'v  is  required,  while  on  sweet  potato, 
apple,  turnip  and  eggplant,  from  three  to  seven  weeks  elapses. 

The  development  of  sclerotia  was  followed  in  Van  Tieghem  cells.  Tlie 
method  employed  wa^  to  pour  enough  of  a  melt<ed  nutrient  medium  on  a 
cover  glass  to  form  a  thin  film.  Aft-or  this  had  cooled,  it  was  inoculateil 
and  inverted  over  the  glass  ring.  If  care  is  taken  in  this  procedure  no 
contamination  results.  By  this  method  it  is  easily  poflsible  to  trace  the 
development  of  a  single  sclerotium  under  high  magnification  of  the 
microscope. 

Some  cases  were  not^nl  where  sclerotia  appeared  to  have  developer!  from 
a  single  mycelial  strand;  in  the  majority  of  cases  observe*!,  however,  sev- 
eral or  a  numlHT  of  strands  were  involved.  Sclerotial  development  is 
pre(»ed(Ml  by  the  formation  of  many  s<*pta.  Short  mycelial  tulies  are 
formed  which  ('onniM't  the  strands.  These  in  turn  become  ver>*  much 
septate,  as  do  the  radial  hyphae  which  are  forme<l  laUT  (fig.  1).  As  tlie 
wlerotiuin  enlarges  the  central  cells  IxH'ome  ccmtorted  and  fonn  a  ctMn- 
pact' mass,  due  p(Thaps  to  the  pn^ssitfe  or  resistan<*e  of  the  out4*r  cells 
(figs.  2,  3,  4).  The  mature  sclerotia  are  coal-black  in  color  and  in  nuirt 
cji.**<»s  are  fnM»  fn)m  any  surface  irregularities  (fig.  5).  No  differences  wrre 
olx^Tved  in  the  formation  or  color  of  s(*lerotia  of  the  different  strains. 

In  tlM»  progress  of  X\u*si*  studies  numerous  instancies  were  oIw^tvih!  wIhtp 
my<*elial  branches  united:  this  took  place  U'twevn  bmnchert  of  a  single 
strand  tis  well  as  lM*twcM»n  two  s<*parate  strands  (fifp*.  G,  7,  8).  In  stmie  few 
ca.*4<»s,  this  was  the  first  i4ep  in  sclerotial  development,  but  usually  tlie 
mycelium  U'comrs  M'ptate  and  irregular. 

Sections  of  the  srlcrotia  of  the  different  strains  showed  them  to  U^aUke 
with  H'gard  to  tlirir  internal  struct unr  (figs.  9  and  10).  In  this  conntv- 
tioii  s4HMis  wen*  S4H'iione<l  to  determine  if  the  mycelium  pi*iu*trat4\i  the 
m^mI  inat,  liut  in  nonr  of  the  viim^  exjimine<l  was  this  ol»siTve<i  to  U»  tru«'. 
The  apiM'aranre  of  x-lerotia  on  the  s4»<mI  did  not  ap|)ear  to  afT«H't  germina- 
tion. Ilralthy  plants  wi»n»  grown  from  disc»;iscHi  setnl.  Measurement.-*  tif 
xUr  M-lt-nitia  gave  nvMihs  identical  with  thos4»  of  Taubenliaus.' 

Atti'iiipt>  to  produti*  a  jHTfecl  .»<tage  faile<l.  In  ever>'  case,  on  the  ger- 
mination i»f  tin*  x-lrrotia  ih'W  sclrrotia  wen»  formed. 

*  J   J   T:tiiNnh:iUh      The  Murk  rntH  iif  th«*  ffWiH't  potato.     PbytopAth.  S:  iy>  \%\ 


19171 


Martin:  Fbutt-Rot  of  Psppers 


SCLEROTIAL    DeVBLOPUENT 


FiOB.  1,  2,  3,  4  and  5.     Stages  in  Brterotial  development. 

Figs.  6,  7  and  8.    Anastoroising  of  hyphae. 

Fig.  9.  SectioDS  through  mature  sclerotia. 

Fig.  10.  Section  of  Bclcrotium  on  epidermis  of  pepper  fruit. 


312  Phytopatholoot  [Vol.  7 

conclusions 

The  pathogenicity  of  Sderotium  sp.  causing  a  rot  of  peppers  {Capsicum 
annum  L.)  has  been  established. 

The  following  facts  warrant  the  conclusion  that  the  sderotiuni  occurring 
on  peppers  is  identical  with  Sderotium  baiaticola  Taub. 

a.  CroHg-inoculations  on  sweet  potato  and  pepper  as  well  as  other  horts 
gave  positive  results. 

6.  With  both  strains  the  growth  was  identical  both  in  culture  and  on  the 
host. 

c.  Measurements  of  the  sclerotia  are  identical. 

d.  Sclerotial  development,  color  and  structure  is  the  same  with  liotb 
strains. 

It  appcjirs  fn)m  these  studies  that  the  charcoal  rot  of  sweet  p«»tat4i«'!* 
(Jinmiaa  batata)  is  common  and  widely  distributed  throughout  «H'tion«i  of 
New  Jers<»y,  that  S.  Imtaiicola  Taub.  can  probably  |x»rj*L»<t  on  several  nthor 
hosts  and  that  it  is  the  (*ause  of  a  di^e:u<e  of  minor  importance  of  p<*p|M*i>. 
Laboh.\T()KY  ok  Plant  Patiioi/kjy     • 
New  Jkicsky  AGKurLTiRAL  Expeiument  Station- 
New  PurxswicK,  New  Jerskv 


A  NECTRIA  PARASITIC  ON  NORWAY  MAPLE 

Mel.  T.  Cook 

During  the  suimner  of  1913  the  writer's  attention  was  called  to  an  in- 
teresting disease  on  a  group  of  Noirway  maples  growing  on  the  private 
grounds  of  one  of  the  residents  of  Princeton,  N.  J.  The  first  symptoms 
of  the  disease  were  the  wilting  of  the  leaves  and  dying  of  branches  very 
similar  to  the  well  known  symptoms  of  the  chestnut  bark  blight  disease, 
caused  by  Endothia  parasitica.  In  fact,  it  was  the  very  striking  resem- 
blance to  the  chestnut  blight  that  attracted  the  attention  of  the  superin- 
tendent of  the  grounds  and  led  to  the  writer's  being  called  to  make  an 
examination.  A  further  examination  of  the  dead  branches  showed  a  still 
more  marked  resemblance  to  the  chestnut  bark  bUght;  the  dead  branches 
had  been  completely  girdled  by  a  canker  which  showed  a  blackening  and 
slight  sinking  of  the  diseased  bark.  The  older  cankers  were  covered  with 
the  orange-colored  pustules  of  the  Tubercularia  stage  of  a  Nectria  and 
there  was  abimdant  evidence  that  this  organism  was  the  cause  of  the 
trouble. 

'  The  superintendent  had  been  watching  the  disease  for  some  time  and 
had  removed  many  dead  branches  and  cankers.  Fresh  woimds  were  very 
quickly  attacked  by  the  fungus,  which  made  its  first  growth  in  the  oozing 
sap,  but  the  careful  treatment  of  these  wounds  with  antiseptics,  followed 
by  an  application  of  paint,  greatly  reduced  the  number  of  infections. 
The  breaking  of  the  small  lateral  twigs  from  the  trunk  and  larger  branches 
was  the  most  common  source  of  natural  infections  and  most  of  the  cankers 
had  started  from  woimds  of  this  kind. 

An  inspection  of  the  trees  on  the  estate  and  in  the  immediate  vicinity 
showed  two  others  badly  affected.  These  were  destroyed,  but  the  clump 
previously  referred  to  was  left  standing  for  observation  and  study.  Dur- 
ing the  remainder  of  1913  the  infected  parts  were  removed  as  soon  as  de- 
tected and  the  wounds  treated.  In  the  fall  of  1913  and  the  spring  of 
1914  heavy  appUcations  of  fertilizers  were  apphed  to  all  the  trees  and  ob- 
servations continued  during  the  smnmer  of  1914.  The  disease  reappeared 
and  the  fungus  was  always  presentr  on  the  cankers,  but  was  much  less 
severe  than  in  1913.  The  fimgus  was  frequently  found  in  the  dead  bark 
around  old  wounds,  but  in  many  cases  did  not  appear  to  be  parasitic. 
About  one-third  of  the  trees  in  this  clump  showed  the  fungus  in  1914. 
Another  clump  of  trees  on  the  opposite  side  of  the  driveway  showed  but 


314  Phytopathology  (Vol.  7 

vcr>'  little  of  the  funf^us.  The  clump  of  trees  has  l)een  kept  under  <»lKM»r- 
vation  (hiring  1015  and  1916,  and  the  disease,  although  present  L*«  much 
less  severe  than  in  1913.  Wounds  are  frequently  infected  but  the  in- 
creased vigor  of  the  trees,  and  the  careful  removal  of  diseased  hranche?* 
as  soon  as  detected,  has  apparently  resulted  in  a  great  re<iuction  (if  th«' 
disease. 

Since  1913  the  writer  has  frequently  found  the  fungus  on  Norway  mnpl<^ 
and  also  on  the  muUxTry,  working  saprophj-tically  and  also  appariMitly 
as  a  weak  parasite. 

The  idea  that  Xectria  Is  parasitic  is  not  new  in  either  Kumpe  or  America. 
Weluner*  reports  having  found  it  on  the  healthy  stumi)s  of  a  cut -over  thi(*ket 
of  tnH»s  and  shruh.*^,  esiKiciiilly  on  Cnrpinus  sp.  He  also  found  a  I>ipl«Mh:i 
and  a  TulMTcularia  on  th<»  young  twigs  of  walnut*  som«»times  associ:it«Hl 
an<l  sonu»tinies  the  Tul>ercularia  growing  alone.  He  states  that  the  twig> 
wen^  winter-kill(Mi,  and  that  the  fungus  gained  access  to  the  host  thn>ugh 
the  dca<l  parts  from  which  it  worke<l  its  way  into  the  living  tbisues.  Tho 
injunnl  twigs  w(T(»  d(»foliat<»d  and  the  tnn*  lK)re  vcr>'  little  fniit. 

It  was  al.*«o  reported  !)y  Hehrcn.s-  as  attacking  Abies  iHilsamnt,  llie 
terminal  buds  wcn»  fr(^<|uently  swollen.  This  wjis  due  to  thr  fomiati<»n 
of  a  laver  of  <*ork  lH'tw(»en  th(»  healthv  and  necnitic  tissues.  Tlir  >\iell- 
ings  of  the  ])r(^vioiis  year  wen*  mo.»<tly  dead.  Some  of  the  gn^Mi  twig>  diii 
not  develop  their  l>ii<ls  and  .•<ome  died  later.  Th<'  myct*lium  hilN'rnat4*<i 
in  the  dead  wood  and  |)<Mietrat<'d  the  living  wcmhI  the  following  .*«4*:lm)ii. 

Thr  mo>t  important  .Vmerican  rejxirt  is  "by  Polh»ck'  who  found  Xtctna 
CiKcinm  (Pers.)  Fr.  causing  cankers  on  yellow  birch.  Thes<»  cank<T>  fre- 
(jucntly  ginllc  the  infected  parts.  In  cas<»  <>f  inftvUMi  twigs  hy|M*rtn>phics 
w<'n*  frMiueiitly  fornuid.  Sevctral  Am<Tican  students  have  rf*|>ort4Hl  >tmi- 
lar  observations  to  the  author. 

Atiitn  ri/n  KVL  Kxpkuimknt  Station 
Nhw  HHrN>wirK.  Nkw  Jkii.skv 

»  Wf-hintr.  ('  Zuni  PrirrfitiMiiniH  v<i!i  Nrrtriii  rinnjilmrinn  Fr.  Z«*it.  Pflniitrnkr. 
4:71  s|      1V»I 

'  |i<l»r«'n-  J.  Kill  iH-iiHTki'iiKWiTtrH  Vorkniiinicti  von  "NiTtria  ritiiiabannA" 
iiritl  till'  \•Tl»^l'ltllIlK^•M^lHl•  ilif*it'M  Pil/c}«.     Zt'it.  PtlHiizriikr.     6: 1*.K{  \\Ps.     Ivj.'i 

■riiliiMk.  J.   IV     A  <-:ttiktr  (III  vi'llow  hirrh  ami   :i   NciMriii  aumM-inlod  with  it 
I{«-|)t     Mull.  Ar.'ui    Srifiiif      7:  1*.K).V 


PHYTOPATHOLOGICAL  NOTES 

Notes  on  Razoumofskya  campylopoda.  Berries  of  the  false  mistletoe, 
Razoumofskya  campylopoda  (Engelm.)  Piper,  growing  on  Pinus  sabinianaf 
were  collected  by  Dr.  E.  P.  Meinecke  in  the  San  Rafael  Mountains,  Santa 
Barbara  County,  California  (Forest  Pathology  No.  17026),  November  12, 
1914,  and  sent  to  the  writers.  Seeds  from  these  berries  were  used  No- 
vember 19,  1914,  for  inoculating  yoimg  pine  trees  in  pots  as  follows: 
one  Pinus  hanksiana  Lamb.,  one  P.  bungeana  L.,  four  P.  caribaea 
Morelet,  four  P.  contorta  Loud.,  two  P.  couUeri  Lamb.,  one  P.  densiflora 
Lieb.  &  Zucc,  two  P.  halapensis  Mill.,  six  P.  mayriana  Sudw.,  two  P. 
monophylla  Torr.  &  Frem.,  one  P.  nigra  Arnold,  two  P.  parvifiora  Lieb.  & 
Zucc,  six  P.  pinaster  Ait.,  one  P.  pinea  L.,  one  P.  resinosa  Ait.,  two  P. 
rigida  Mill.,  four  P.  sabiniana  Dougl.,  one  P.  strobu^  L.,  and  two  P. 
virginiana  Mill.  Two  trees  of  Larix  ocddentalis  Nutt.  and  two  of  Pseu- 
dotsitga  taxifolia  (Lam.)  Britton  were  also  inoculated.  The  trees  used 
were  from  three  to  six  years  old.  The  seeds,  enclosed  in  pxilp,  were  placed 
chiefly  in  the  axils  of  the  leaves  on  the  younger  portions  of  the  shoots, 
adhering  firmly  as  soon  as  the,  pulp  dried.  Many  germinated,  but  the 
radicles  of  only  a  few  succeeded  in  penetrating  the  bark  of  the  trees  on 
which  they  were  borne.  In  six  months  plants  became  established  on  the 
following  species  of  trees:  one  Pinus  banksiana,  one  P.  bungeana,  one 
P.  caribaea,  one  P.  pinea,  two  P.  sabiniana,  and  two  P.  virginiana.  On 
Pinus  bungeana  and  P.  virginiana,  dense  witches-brooms  formed  around 
the  mistletoe  infested  region.  On  the  other  species  spindle-shaped 
swellings  without  witches-brooms  were  usually  produced  at  the  point  of 
attack.  All  these  trees  except  Pinus  sabiniana  are  new  hosts  for  this 
species  of  mistletoe  in  this  country. 

All  the  trees  inoculated  successfully  produced  clusters  of  mistletoe 
plants  in  1916,  none  of  which  produced  mature  fruits,  apparently  owing  to 
lack  of  fertilization.  In  1917  mistletoe  plants  are  again  developing  on  all 
trees  except  those  with  dense  witches-brooms. 

The  effect  of  the  mistletoe  is  to  stunt  appreciably  the  growth  of  all  the 
trees  inoculated,  as  compared  to  other  similar  trees  of  the  same  species 
not  inoculated.  Only  one  of  the  trees  successfully  inoculated  has  died 
from  this  effect  after  two  years'  growth,  one  of  Pinus  virginiana  with  a 
witches-broom.  In  case  of  trees  of  the  same  species  inoculated  imder 
similar  conditions  with  Peridermium  cerebrum  Peck,  and  P.  harknessii 


316  Phytopathology  (Vol.  7 

Mooro,  nearly  50  per  cent  of  the  infected  tnH»s  diinl  inside  of  two  yrars, 
indicating  that  the  stem  rusts  are  much  more  clestructive  t4>  young  pim* 
than  the  falw*  mistletoi»8. 

Th(»  mistletoe  is  a  western  species  which  grows  \igorousIy  on  ea»*t«m 
spiK'ies  of  pines.  Since  the  infect e<l  areas  on  young  pines  may  not  !>*• 
conspicinais  during  the  first  w^ason's  growth  and  l)ecause  of  the  fact  that 
the  aerial  parts  of  the  mistletm*  ])lants  are  annual,  and  an;  not  usually 
observed  on  donnant  trees,  insjM»cti(m  of  nurser>'  st^ick  is  nt)t  sufficient  to 
insure  its  freedom  fr(»m  this  harmful  parasite.  Shipments  fn»m  the 
Roeky  M<»untain  and  Pacific  regions  to  thos<'  farther  east  should  hi*  fli-*- 
couraged*  as  they  are  likely  to  carr>'  the  mistletoe,  even  though  they  may 
ap])ear  clejin.  (hir  east<*rn  pines  are  at  j)res<*nt  fn»e  from  mistlet<N\i.  and 
should  remain  so. 

(Iko.    (i.    IlKIMit'CMK    AND    N.    HkX    HiXT 

Tht    prtufuctinn   itf  spons  by  AUiTfiaria  Sobini  in   purr  culiurr,     Thi?* 
fimgus  has  Immii  the  sul»JM*t  of  s])e<-ial  stu<iy  l»y  thf  auth(»r  at  th«'  I'ni- 
versity  of  Wisc<»nsin  during  the  i)ast  three  yrars.     The  seiireity  of  ••pun* 
pnxhiction  in  jHin*  rultures,  which  has  \HH*n  not**^!  l»y  pn-vitnis  work#r«. 
was  at  th«*  nutst't  a  hindnnu'e  to  iuo<'ulation  experiiiM-nts.     TriaN  with 
twrnty  difTrrt'iit  kiii<ls  of  iiuMlia  including  some  tr>ts  <in  thi*  fffti't  nf 
variation  «»f  :u'i<lity  :iud  tt'inpfrature  wen*   iiiadi-,   hut    thr    n*Milt    w.i«* 
always  tin*  samr,  frw  Np<.n's  luing  pmduefd.     In  Ffl»niar>'.   llU.'i.  ••\- 
pt-rinirnts  wt-rr  Ingun  in  whi<"h  the  moistun*  enntmt  of  thi*  mrtlium  anil 
th<-  huiridity  «»f  thi'  :ur  al»«>Vf  1h<-  rujture  wrre  varit-d.     Thi**  lik«-\%i'^- 
was  without  ri>ult>  rxrrpt  whui  tin-  eulttin*  was  shrt'ddrd  antl  thr  iii>  rt- 
hum  srvmly   woiunltd.     Tinlrr  >urh    tn*atmi*nt   ennrmi»us  *i|Minilatioii 
w:i«»  alway>  mtup  d   ifig.    I.   liK     A  f«'W  hjMjrrs  wtTi*  foriiird   whm  th»- 
invrt'liiini  aloiu-  \va>  eut.     Thr  iiio>t  sur<'i'ssful  lUfthod  eonsi>ts  in  gn»w- 
iiig  tJif  Alti-rnaria  m  pttri  dish  eultun*,  on  liard  ix»tat«»  agar,  for  ti  n  t«» 
t^\»  Ivi   I  lav-,  till  II,  lir^t,  »»hn'dding  thi-  ag.ar  to  liits  (fig.  1,  ^4  »  and  >tirnne 
ti»    -I  parati-    aii«i    i  v«nly    diMrihutf    tin-    pitrrs;    s<*<'ond.    contniHini:    f«'r 
t\v«nt\-fnur  1m  fnrtv-iiuht  honrs  tlnnaftrr  thi*  mojMurr  nlation  ^.  that 
jiarti.il  ilr>inu  out  i<  itY«rt«'«i  without  :dli»wing  tht*  more  exposed  -urfai  • -* 
Tc  Im  ( i.rcr  i:(*-i(iatt  «i  and  hai»l.     'V\m-  lattrr  ol»ji-<*t  is  acrompli*ih(*«l   imi-t 
n  a«:i!\  l\  r«  ri.iviiii:  t  l:i  lid  and  i  \|M'-iiii;  thi-  di<h  t4»  sunlight  in  a  >tinliz«  d 
riji  !-•  <  1. .1/1.1  r  I'T  1h]1   i:ir.      It  »  vapi»rati«»n  i-  to«i  rapiil.  on-a'^ioiud  :it<- 
II  i/mi:  ui»!:   -ttiili/ii!  \\:ttir  i-  n«  ci  «»-ary.     Spon-s  W(*re  «il'taintil  \*y  thi* 
J- •  t :  I  d  III  t.»:tl  iliiikii' --  in  »!n    iriiul'atur  at  *J»i    ( '.  hut  tIomt  att«iitii*n 
\\  :     r«  'iijii'  ■!. 

*'*.-!?:•   .  uT  jii.l  t  \]i'  -I  •!  -nrf:ii  t  -  ni  thi  :iuar  thi  ndivrlop-  fn»m  th«  "-id 
ri.'''!iir'     t   ii'U\..ik  «  t"  rl..-i|v  -t  ptati-.  t  l-.iik-wallrd  hyphar.  from  whii'h 


1917]  Phytopatholoqical  Notes  319 

Phytaphthora  infestans,  causing  damping-off  of  tomatoes.  Phytophthora 
infestans  has  been  recorded  as  occurring  on  tomatoes  by  both  American 
and  European  pathologists.  So  far  as  literature  on  the  subject  is  avail- 
able to  the  writer,  no  one  appears  to  have  noted  this  organism  as  causing 
damping-off  of  yoxmg  tomato  plants.  The  following  brief  accoimt  of  a 
severe  outbreak  of  damping-off  of  tomatoes  caused  by  Phytophthora 
infestans  may  be  of  interest  therefore  to  pathologists. 

In  June,  1916,  a  number  of  young  diseased  tomato  plants  were  received 
by  the  Ontario  Agricultural  College  from  J.  W.  Noble,  Essex,  Ontario. 
In  the  letter  accompanying  the  plants  Mr.  Noble  stated  that  thousands 
of  late  tomato  plants  in  that  district  had  been  destroyed.  The  affected 
plants  were  first  observed  shortly  after  the  tomatoes  were  set  in  the  field. 

A  glance  at  the  plants  revealed  brown  lesions  and  constrictions  on  the 
stems  near  the  surface  of  the  groxmd.  Many  of  the  plants  showing  these 
symptoms  had  fallen  over,  due  to  the  collapse  of  the  stems  at  this  point. 
On  examining  the  stems  with  a  hand  lens  a  white  fimgous  growth  was 
clearly  seen  on  the  lesions.  This  when  examined  \mder  the  microscope 
proved  to  be  the  conidiophores  and  conidia  of  Phytophthora  infestans 
(Mont.)  deBary.  After  this  all  the  plants  were  examined  very  carefully, 
and  on  some  of  them  the  same  fimgus  was  found,  apparently  causing  a 
blighting  of  the  leaves;  but  the  chief  damage  done  jbo  all  of  them  was  by 
the  destruction  of  the  stem  near  the  surface  of  the  ground.  The  falling 
over  of  the  plants  by  hundreds  in  the  field  was  what  first  brought  the 
disease  to  the  attention  of  the  growers. 

Some  idea  of  the  severity  of  this  outbreak  of  damping-off  of  tomato 
plants  may  be  had  by  considering  the  fact  that  out  of  288,175  tomato 
plants  supplied  by  the  Heinz  Pickle  Company,  Leamington,  Ontario , 
to  Pelee  Island  growers,  only  45,000  reached  maturity.  At  least  50  per 
cent  of  the  plants  that  did  not  survive  succumbed  to  damping-off  due  to 
Phytophthora  infestans. 

It  is  interesting  to  note  that  weather  conditions  during  June  were 
exceptionaUy  favorable  to  the  spread  and  development  of  Phytophthora 
infestans,  the  rainfall  being  much  above  the  average  for  June,  and  the 
temperature  relatively  low. 

J.  E.  HowiTT 

State  and  National  quarantines  against  the  white  pine  blister  rust.  The 
following  table  shows  the  State  and  National  quarantine  action  taken  to 
date  against  the  white  pine  blister  rust.  The  action  is  so  varied  in  char- 
acter that  it  seems  necessary  to  present  it  in  this  form.  Similar  action 
is  under  consideration  in  a  number  of  other  states. 


320 


Ph  ytopatholoo  y 


(Vol.  7 


arses. 

UTAT* 

WaiTB  riMBS 

OSOMrLAS- 
lA 

DATS 

QCASAMTIXBD    ABBA 

CJanadfi 

All 

None 

November  14, 

All  foreign  countries 

^^^^••••M^4M  ••••■•••• 

1914 

United  States.. 

P.  strohus, 

None 

September  16, 

Great   Britain.   France, 

monti- 

1912 

Helipum.        Holland. 

cola, 

Denmark,       Norway. 

laml>er- 

Sweden.  Kuasia.  i^wrr* 

tiana, 

many,  Austria,  Italy. 

cembra 

Switserland 

All 

None 

May  21.  1913 

Kurope  and  Asia 

All 

All 

March  10,  1916 

Canada  and  Newfound- 
land 

All 

All 

June  1.  1917 

All  points  east  of.  and 
including  the  states  of 
Minnesota.  Iowa. 
Missouri.  Arkansas. 
I^uisiana 

AH 

U.     ni- 
fcruni 

June  1,  1917 

States  of  New  Kngland 
and  New  York 

None 

All 

Juno  1.  1917 

Kurope  and  Asia 

(California 

All 

All 

February,  1917 

F^ist  of  Mississippi  Ki%'er 

Delawan* 

All 

All 

March  2.  1917 

All  |K)ints  outside  state 

Idaho 

AIL 

All 

March  1,  1916 

New  IIam|Nihire,  Ver- 
mont, Massachusetts, 

• 

Connecticut,  New 
York.  Pennsylvania 

Indiana 

All 

All 

March  13.  1917 

All  |M>ints  outside  state 

KanHaa 

All 

All 

March  10.  1917 

All  |Miints  outside  state 

MaMuichuBctta  . 

All 

None 

June  1.  1912 

Kun)|ie 

MicluKAn 

All 

All 

March  19.  1917 

All  |M>ints  outside  state 

Minnesota 

All 

None 

Apnl  30,  1917 

Maine.  New  Hampshire. 
Vermont.  Maasarhu- 
si*tts.  RhrMie  Island. 
Cofinertimt.  Nrw 
N  ork.       N«'W       JvTm  \  . 

Pennsylvania,  uhi<i. 
Wisconsin 

Montana 

All 

All 

July  17,  1916 

New  llampshirr.  Vrr- 
mont.  Massachusetts. 
(Connecticut,  New 
York.  Pennsylvania 

Nrvftd.n 

All  pines 

1 

1 

All 

1 

March  10,  1917 

Fast  of  Mississippi 
Kiver  and  Minnesota: 
all  foreign  countries 

Nr*»  Jrrwy 

All 

1 

1 

1       NolM' 

April  16.  1917 

Maine.  New  llamfishire. 
Vermont.  Massachu- 
setts, Rhode  Island. 
Connect tcut.  IVnnsyl- 
vania.  New  York. 
Minnesota.  Wisconiun 

1917] 


Phytopathological  Notes 


321 


BTATB 


New  York. 


Ohio. 


WHITE  PINES 


All 


RIBE8, 

OROSSniiAR- 

lA 


None 


DATE 


March  24,  1917 


Oregon. 


Pennsylvania. . . 
South  Dakota^... 
West  Virginia... 
Wisconsin...' 


P.  strobus, 

None 

monti- 

cola,lam- 

bertiana, 

cembra, 

excelsa, 

flexilis 

All 

All 

All 

None 

All 

All 

All 

All 

P.  strobus, 

None 

monti- 

cola,  1am- 

bertiana, 

cembra. 

excelsa 

February  21,  1917 


QUARANTINED  AREA 


July  24,  1916 


March  12,  1917 
April  3,  1917 
April  18,  1917 
June  1,  1916 


Ohio,  Indiana,  Min- 
nesota, Wisconsin, 
Maine,  New  Hamp- 
shire, Vermont,  Mas- 
sachusetts, Rhode  Is- 
land, Connecticut, 
Pennsylvania,  Illi- 
nois,   New   Jersey 

All  points  outside  state 


East  of  Mississippi 
River;  all  foreign 
countries 
All  points  outside  state 
All  points  outside  state 
All  points  outside  state 
All  points  outside  state 


Perley  Spaulding  and  Roy  G.  Pierce 

Personals,  Arthur  S.  Rhodes,  assistant  in  forest  botany  at  the  New 
York  State  College  of  Forestry,  Syracuse,  New  York,  has  been  appointed 
assistant  in  the  Office  of  Forest  Pathology,  Bureau  of  Plant  Industry. 

Miss  Ruby  J.  Tiller,  scientific  assistant  in  the  Office  of  Forest  Pathology, 
Bureau  of  Plant  Industry,  has  resigned  her  position  to  become  the  wife 
of  Prof.  S.  F.  Acree  of  the  University  of  Wisconsin. 

Prof.  L.  H.  Pennington  of  the  New  York  State  College  of  Forestry, 
Syracuse,  New  York,  has  accepted  a  temporary  position  as  expert  with  the 
Office  of  Forest  Pathology,  Bureau  of  Plant  Industry.  Doctor  Penning- 
ton will  have  charge  of  the  season's  work  on  white  pine  blister  rust  eradi- 
cation in  the  state  of  Michigan. 

Mr.  G.  H.  Godfrey,  of  Iowa  State  College,  was  appointed  scientific 
assistant  in  Cotton,  Truck  and  Forage  Crop  Disease  Investigations, 
Bureau  of  Plant  Industry,  effective  June  8.  Mr.  Godfrey  was  formerly 
scientific  assistant  in  Cereal  Disease  Investigations,  but  during  the  past 
year  was  granted  leave  of  absence  to  engage  in  post-graduate  study. 


LITERATURE  ON  PLANT  DISEASES 

Compiled  bt  Eunice  R.  Oberlt,  Librarian,  Bureau  or  Pu^nt  Induhtrt.  akd 

Florence  P.  Smith,  Absihtant 

April  to  May,  1917 

American  Phytoptthological  Society.    Report  of  the  eighth  annual  meeting.     Phyto- 

patholojo'  7:  14,>-149.     Ap.  1917. 
Pacific  Division.    Report  of  meeting    ....      Phytopathology  7:  l.SO- 

151.    Ap.  1917. 
Held  at  UnivcrHity  of  California.  Rerkelcy,  D.  2K  and  29.  19!r>. 
Anderson,  Jacob  Peter.    Plant  diiieases.    Alnnka  .\gr.  Kxpt.  Sta.  Rpt.  191i:  .19  41 

1910. 
Ashby,  S.  F.    Report  on  l<*af  R|>ot8  of  okra  and  tomato.    Jour.  Jamaica  .\gr   Soc. 

21:  13.    Ja.  1917. 
(Vrrospora  on  okra;  Cladonporium  fulrum  (m  tomato. 
Australia.    Minister  of  Lands.     I)i8ea«efi  in  plane  trees.     .Aust.  Internat.  NurM-rv- 

munl6.  no.  2:  15.     F.  1917. 

Ur|M)rt  of  c'onferenrr  relative  to  arrioufi  fungoid  diiieaee.  which  has  recently 

Imth  attacking  plane  tn*cH. 
Avema   Sacca,   Rosarto.    MolcHtiiis   cryptogamiriifl   do  caf6eiro.     IM.    Agr.    i.Sln 

Piiulo):  17:  S7S  922.  ilhw.     N.  1910. 
MoIcHti:!.**  (Typtoganiirafl  da  canna  do  aMUcar.  R<>1.  Agr.   (Siko  Paulo)  17: 

IW-lKiS.  illiw.     I).  1910. 
Bancroft,  C.  Keith.    Tht*  Iraf  ditvenfip  of  ruhlMT.    CNinditionn  in  Surinam.     Jour. 

]\i\.  Agr.  Hrit.  (luiana  10:  93  1(».     Ja.  1917. 
Beattle,   Rollo   Kent.    TUv   intriMlurtion   of   fon*ign   plant    diM*a»eii.     (.\lwtrairt 

Sriinn-  n.  H.  46:  139.     .My.  1.  1917. 
Bethel,  Ellsworth.     Pun-inia  Hultnitrnn  and  ittt  iu>fial  hunts.     I'hytopatholog>   7: 

H2  'M.     Ap.  1917. 
Bols,    D^slri.     Snnt'>t«'    dr    |iatltologir    v^grtalr.     Stance   du   2   mars    1917.     \U-\- 

Unrt    89:  "JIM      .Mr.  10.  1917. 
Brown,  Harry  Bates.     I.ifr  Iti^tnry  and  poisonfiUH  pro|»orti«*s  of  (Mavicciw  panpali 

Jniir    \4!r    Ki  ..«:irrli  7:  40l    t<N>.  2  ««  .  pi   .TJ.     N.  27.  1916. 
Brunner,  Stephen  C.     Jd'pnrt  uf  a  irip  to  Pinar  did  Rio.|     .Xgricultun*  jCulia'  1: 

■JJ  J**.      I     1917. 
Burkholder,  Walter  H.     'Mh-  ]HrfiTt   htap*  of  (ilceoHlNiriuni  vi>ni*tiun.     Phylopa- 

thnlnirx  7:  <»  *i|.  3fik[.     .\p.  1917 

/*.'»|-.'m»/-   ■"  f  I'/'l    \  I  1.1  til    II       Mp, 

Butler,  Edm'ln  John.     'Ihi-  dir-fiiiiiKitinii  i»f  p:ir:ii«itir  fungi  and  international  Irgis- 
l.»ti..!i      Mini    Dfpt.   Visr.  India  Hnt.  St.  9.  no.  I,  73  p.     F.  1917. 

Chtlds,  Leruy.     <  il>«i-r\  :itifi>.>*  <iii  tin-  r«-l:iti«>n  of  thr  hi'iglit  of  fruit  to  apple  scab 
iiif>.*ii>ii      ()ri-k:<>it  Awr.  Kxpt    St:i    Hnl    111:1   17.  0  fig      1917. 
Ki-piirt  4i(  thi-  lltMMl  Kivi-r  )ir:iiii-h  rxpi-niin  lit  ittatioh  for  1916. 


19171  Literature  on  Plant  Diseases  323 

Cook,  Melyille  Thurston.    Report  of  the  department  of  plant  pathology.    New 
Jersey  Agr.  Expt.  Sta.  36th  Ann.  Rpt.  [1914]/16:  365-374.    1916. 
Most  common  diseases  of  the  year,  p.  367-374. 
Darnell-Smith,  G.  P.     ''Brown  spot"  of  Emperor  mandarins.     Elxperiments  in 
its  control.    Agr.  Gas.  N.  S.  Wales  28:  190-196.    Mr.  1917. 

The   prevention   of   bunt.    Experiments  with   various   fungicides.    Agr. 

Gas.  N.  S.  Wales  28:  185-189.    Mr.  1917. 
Doidge,  Ethel  M.    A  bacterial  spot  of  citrus.    Ann.  Appl.  Biol.  8:  53-81,  pi.  3-13. 
Ja.  1917. 
Literature  cited,  p.  80. 
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Elliott,  John  Asbury.    The  sweet  potato  "soil  rot''  or  "pox/'  a  slime  mold  disease. 
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Fawcett,  Howard  S.    A  bark  disease  of  avocado  trees.    Ann.  Rpt.  California  Avo- 
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Freiberg,  Geoige  W.    Studies  in  the  mosaic  diseases  of  plants.    Ann.  Missouri 
Bot.  Gard.  4:  175-232,  pi.  14-17.    Ap.  1917. 
BiWiography,  p.  223-225. 
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Carman,  Harrison.    A  new  sweetcorn  disease  in  Kentucky.    Kentucky  Agr.  Expt. 
Sta.  Circ.  13,  4  p.,  illus.     1917? 

Destructive  bacterial  disease  undoubtedly  the  same  as  that  described  in  1897 
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Bol.  Agr.  [Sao  Paulo]  17:  873-878,  illus.    N.  1916. 
Giissow,  Hans  Theodor.    Report  of  the  division  of  botany.    Canada  Expt.  Farms 
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Harris,  James  Arthur.    The  application  of  correlation  formulae  to  the  problem  of 

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Decay  in  timber  is  almost  exclusively  due  to  the  action  of  fungi,  the  greater 
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organisms,  namely,  the  Hymenomycetes. 
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Occurrence  in  United  States. 


324  Phytopathology  [Vol.  7 

Jensen,  Charles  A.    CompoHition  of  citrus  leaves  at  various  stagi's  of  ntfittlioK. 
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jll'j-      M\    l'»17 


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and  Toan,  Lewis  A.    Control  of  leaf -curl  disease  of  peaches.    Proc.  West. 

New  York  Hort.  Soc.  62:  28-32.     1917. 
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Phytophthora  lerrestria  n.  sp. 
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References  in  footnotes. 
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Stevens,  Ftank  Lincoln.    Noteworthy  Porto  Rican  plant  diseases.    Phytopathology- 

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Stevens,  Neil  Everett,  and  Wilcox,  R.  B.    Rhizopus  rot  of  strawberries  in  transit. 
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Literature  cited,  p.  21-22. 
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iPiiYioi'Mii(»LcHiY,  for  Juiu\  I1M7  '7:  \'ut'2'Mi  wan  iiwued  June  2.  1917  , 


PHYTOPATHOLOGY 

VOLUME  VII  NUMBER  5 

OCTOBER,  1917 

ALTERNARIA  ON  DATURA  AND  POTATO 

R.  D.  Rands 
With  Four  Figures  in  the  Text 

During  the  progress  of  studies  on  the  early  blight  of  potato  caused  by 
AUernaria  solani  (E.  &  M.)  J.  &  G.,  an  investigation  has  been  made  of  the 
various  host  relations  attributed  to  this  fungus.  Throughout  the  litera- 
ture the  early  blight  organism  is  claimed  to  be  the  cause  of  the  leaf-spot 
of  Jimson  weed  {Datura ^  various  species).  One  author  (Chester,  1892) 
goes  so  far  as  to  state  that  this  was  probably  the  original  host,  the  fungus 
going  from  it  to  the  potato  and  tomato.  The  object  of  this  paper  is  to 
present  some  comparative  studies  of  early  blight  and  the  Datura  leaf-spot 
in  order  to  clear  the  apparent  misunderstanding  of  the  relationship  be- 
tween  these  two  diseases. 

The  Datura  leaf-spot  has  been  under  the  observation  of  the  author  in 
the  University  Pharmaceutical  Garden,  Madison,  Wisconsin,  during  the 
summers  of  1915  and  1916.  The  spots  show  a  zonation  similar  to  that 
of  early  blight  but  they  are  straw  colored  rather  than  deeply  stained 
(fig.  1).  They  first  appear  on  the  lower  more  shaded  leaves.  Under 
favorable  conditions  the  disease  spreads  gradually  upwards  when  finally, 
in  late  autumn,  the  seed  pods  often  develop  dark  sunken  lesions  (fig.  2). 
When  a  leaf  becomes  weakened  by  a  number  of  enlarged  spots  it  is  usu- 
ally shed  from  the  plant. 

The  disease  was  noted  on  the  following  species  and  varieties  growing  in 
the  Pharmaceutical  Garden  September  15,  1915:^ 

Datura  tatula  Linn.,  D.  tatula  inermis,  D.  stramonium  Linn.,  D.  stramon- 
ium inermiSj  D.  stramonium  gigardeum,  D,  inermis  Jacq.,  D,  fastuosa  Linn., 
D.  ferox  Linn.,  D.  laeviSj  D.  querdfolia  H.  B.  K.,  D.  leichardtii  F.  Muell., 
D.  metel  Linn.(?). 

*  The  species  and  varieties  are  listed  in  the  form  in  which  they  were  found  on  the 
garden  labels.  Since  the  seed  was  originally  of  German  origin  the  names  are  pre- 
sumably those  in  common  usage  in  the  foreign  seed  trade. 


328  Phytopathology  (Vol.  7 

The  pod  blight  was  especially  conspicuous  on  D.  tatula  inermin.  ftra- 
manium  inermis  and  fastuosa^  while  the  leaf-spot  occurred  on  all  to  a 
greater  or  less  extent.  Datura  stramonium  giganleum  showed  grpater 
resistance  than  the  others. 

ECONOMIC   IMPORTANCE   OF  THE  DISEASE 

As  is  well  known,  the  Datune  furnish  one  of  the  sources  of  the  drug 
atropin  or  daturin  which  is  obtaineil  from  the  leaves.  The  leaves  are 
picked  in  late  Septcmlx»r  sufficiently  early  to  avoid  frost.  It  is  evident 
that  anything  which  tends,  particularly  in  the  latter  part  of  the  9ew^m. 
to  reduce  the  leaf  an*a  st»riouslv  interferes  with  its  economic  use.  Ki^tiniatrs 
made  in  SeptemlHT  11)15,  placnnl  the  average  for  all  varieties  at  M)  to'iO 
per  cent  of  the  total  leaf  surface  destroyed.  The  dr>'  season  of  llUli  pn^ 
ventetl  much  apiK»araiice  of  the  disease*  prior  to  the  rains  of  SeptenilnT. 
But  even  after  that,  favorable  weather  continuing,  a  loss  of  10  to  15  |mt 
ct»nt  in  leaf  area  occurn'd. 

1I18T(»IIY    OF    TIIK    DISEASK    AM)    ITS    CD.NFl'SIOX    WITH    EARLY    HLKiHT 

The  first  refenMic(»  inferring  that  a  n^lationship  exists  l>etwe«»n  this* 
disease*  and  early  blight  is  that  by  (\K)ke  ( lS8.*i).  He  d<»scril)es.  as  though 
they  wen*  i<ieiitiral.  the  fungus  fn)iii  Datura  and  that  fn)m  the  tomato  .v 
Macrof<f)ifrium  solani  (*<M>ke.  Me  was  apimn'iitly  unaware  that  tlu*  same 
binomial  had  Im^mi  applied  by  KUis  an<l  Martin  to  a  simikir  fungus  ontlie 
I)otato  the  yi'ar  U'fon'.  Sareanlo  (ISStij  lists  Cooke's  fungus  as  .Wnrri*- 
^fHtnutn  nn»hi  Saec.  I>iit4T  Kllis  (s<»<»  .Iom*s  ISIW)  affirms  that  this  is  the 
saiiM*  fungus  whieh  he  and  Martin  deseriU'd.  Thiw  the  confu.iion  wnmu^ 
to  have  originated.  It  is  shown  by  the  follr»wing  n'fen»nces  which  an*  a|»- 
pan-ntly  ronrerned  with  this  Datura  leaf-s|K)t.  Kellemian  (ISHo)  fn»!n 
Manhattan.  Kan>as.  Halsted  i  IS*KV)  from  New  Jer>*ey,  Briosi  and  C'avara 
<lV»2i  and  Terrari**  '  P.M^V)  fn>m  Italv.  St4»vens  ilSlMi)  fnnnOhio.  I'mltT- 
\mhh\  iin«l  liailr  lV.»7i  and  Atkinson  ilS*»7)  fn>m  .\lal)ama,  Jon^^  an^i 
<Irniit  |s*»7i  :nnl  Orton  isiHji  funi  V«Tniont.  So  far  as  the  hteraiure 
n'\i:il>  thr  ab«»vr  determinations  were  bas4'd  entin*ly  on  liiorphol«»|cir:d 
evitli-rni  and  on  tin-  Niinilarity  of  the  <lis4'ast»  to  early  blight  of  pi»tat«» 
an<l  iiMt  nil  iii<>iiil:itinn  work  with  the  causal  organism. 

In  onl«  r  to  ilrtiTniinr  wliether  the  leaf->|><tt  as  found  at  Madinm  i*^ 
iIh-  ^aiiif  a*  that  r('|Nirt4'd  i-UrwIuTe.  ex>i«*eat:M'  lalti'lkHl  .W#ifriv/h»»-;:*Fn 
.^"''  i  .  (V  M.  on  Datura.  Were  e\annnt>d  and  eoni|KinMl  with  typir:tl 
in;it«i.:il  lol'ii  .  i«i|  JM-rr.  Tlif  ni.irroMopie  apfN-araiiee  of  the  S|X>ts  of  tlif» 
<\  .'.i^ii-  ni   Si\nHi;ir  ami   I-irlr     No.  lilo,  and  other  eollection?»    fn»m 


1917]  Rands:  Alternaria  on  Datura  and  Potato  331 

atomized  with  a  spore  suspension  in  water  and  for  forty-eight  hours  kept 
moist  by  a  fine  spray  from  a  nozzle.  In  most  eases  reisolations  made 
from  the  infected  plants  were  successful. 

On  September  4,  1916,  further  inoculations  with  spores  of  AUernaria 
solani  were  made  on  mature  potato  and  Datura  plants  growing  in  the 
field.  Several  leaves  were  atomized  with  a  heavy  spore  suspension,  while 
with  others  spores  were  introduced  into  pimctures.  Successful  reisola- 
tions of  the  fungus  was  secured  from  both  atomized  and  needle  punctured 
leaves  on  the  potato.  In  one  instance  tissue  plantings  from  the  browned 
needle  punctures  on  Datura  stramonium  five  weeks  after  inoculation  gave 
the  fungus.  The  results  corroborate  the  green  house  tests  and  show  that, 
in  no  case,  was  A.  solani  able  to  form  spots  on  even  the  old  and  weakened 
leaves  of  Jimson  weed.  However  in  toto  fixations  showed  that  penetration 
and  incipient  infection  occurred  in  many  .cases.  But  the  fungus  seemed 
unable  to  establish  itself  and  bring  about  enlargement  of  the  spot. 

inoculations  with  the  fungus  from  datura 

The  Madison  culture  of  the  parasite  from  Datura  stramonium  was  tested 
comparatively  first  in  the  greenhouse,  and  later  in  the  field  on  Jimson 
weed,  potato,  tomato,  and  on  Solanum  nigrum,  the  common  black  night-, 
shade.  Several  methods  of  inoculation  in  which  myceUum  or  spores  wei'e 
placed  in  needle  pricks  and  the  spores  atomized  upon  the  surface  were 
used.  Most  of  the  tests  were  carried  out  at  the  same  time  and  under  the 
same  conditions  as  those  already  reported  with  Alternaria  solani  from 
potato.  These  experiments  may  be  briefly  summarized  as  follows:  On 
the  Jimson  weeds  including  Datura  stramonium,  D.  inermis,  and  D.  tatula, 
typical  spots  3  to  10  mm.  in  diameter  invariably  resulted  after  two  weeks. 
On  potato,  tomato  and  Solanum  nigrum,  incipient  infections  in  the  form 
of  tiny  brown  specks  often  occurred.  They  were  less  abundant  on  the 
nightshade  and  vigorous  leaves  of  tomato.  These  spots  in  no  case  en- 
larged, even  after  the  leaves  were  yellowing  and  dying.  The  fungus  was 
reisolated  readily  from  the  Datura  leaves  but  only  in  a  few  cases  could  it 
be  obtained  from  the  incipient  spots  on  the  other  plants.  The  needle 
punctures  on  the  latter  were  in  most  cases  entirely  healed  after  eight  days. 
Therefore,  it  appears  that  we  have  here  an  Alternaria  which,  though  bear- 
ing much  superficial  resemblance  to  AUernaria  solani,  is  nevertheless  dis- 
tinct in  its  host  relationship.  In  no  instance  has  there  been  observed  any 
crossing  over  to  the  potato  or  other  hosts  of  A,  solani  tested,  and  also  no 
crossing  of  the  potato  fungus  to  Jimson  weed.  The  above  conclusion  is 
further  confirmed  by  a  comparison  of  the  two  fungi  in  other  particulars. 


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Rands:  Aia^bnaria  on  DATxmA.  and  Potato 


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334  Phytopathology  (Vol.  7 

comparison  of  the  fl^gus  from  datura  with  alternaria  80l.\m 

On  hard  potato  agar  the  colony  of  Altcrnaria  from  Datura  is  at  first 
of  a  light  olivacious  color  with  faint  pinkish  margins;  later  the  entire 
growth  becomes  a  grayish  white  while  from  the  lower  surface  often  blackish 
mycelium  can  be  seen  through  the  agar.  With  A.  9olani  the  grayi^h  or 
brownish  colony  produces  a  deep  pinkish  to  yellowit*h  pigmentation  of  the 
agar  which  often  extends  in  advance  of  the  mycelium  (fig.  3).  This  fur- 
nishes at  once  a  distinct  physiological  ba.^is  for  the  differentiation  of  the 
two  fungi.  Morphologically  they  are  similar  in  many  respects.  <>ne 
of  the  most  prominent  characters  which  distinguishes  the  Datura  f unguis 
from  A,  i<olani  is  found  in  the  terminal  prolongation  or  beak  of  the  spore. 
In  the  former  the  beak  is  coarser,  more  elongated,  rarely  has  any  pro- 
nounced tapering  to  the  tip,  and  is  never  forked  or  divided  (fig.  4).  ( >ften 
a.**  high  as  75  per  cent  of  the  spores  of  -4.  solmii  l)oth  from  cultures  and 
from  s|)ots,  have  l)eeii  ol)ser\'ed  to  possess  forked  or  variously  di\'i*kHl 
l)eaks,  the  sulnlivisions  ta|Kring  more  or  less  to  the  tip.  One  hundred 
HIK)res  from  typical  early  blight  s|X)ts  from  potato  gave  a  range  in  Mie  erf 
12()  to  2<U)  by  12  to  20  /i  and  an  average  of  2(K)  by  17  fi.  With  the  Datura 
fungus  the  range  in  size  was  128  to  448  by  It)  to  40  m  with  an  average  of 
2t)l  by  23  /i-  'i'he  latter  it  is  sc*<*n  has  spores  considerably  larger  in  both 
dimensions  than  -4.  W/iri/.  However,  the  difference  is  not  such  as  to 
make  sjwre  measureineiits  n»liable  when  not  supplemented  by  the  oth«*r 
distinguishing  characters  mentione<l. 

IDENTITY   OK  THE    DATURA    PARASITE 

The  fungus  has  U»imi  refern»<l  to  as  an  Altemaria.  This  was.  howeviT. 
inen*ly  on  account  of  its  great  similarity  to  Aliernaria  nolani.  As  in  the 
(*as4'  of  the  latter,  cultun^s.  on  oatnieal  agar  oi*casionally  develop  f(port>  in 
catcnulute  pairs  (fig.  4).  Acconling  to  the  pn^sent  delimitations  of  ttie 
g(*n<Ta  Alt4*nmria  and  Macros|)oriuni  this  catenulation  of  spores  make:«  the 
fungus  an  Alt4*rnaria.  However,  it  is  n^aliauMl  that  the  conditioa<  under 
wlkirh  s])on'  i>airs  are  fonned  an*  |M>ssibly  abnonnal  and  it  is  doubtful 
if  the  fungus  U'liavf^s  similarly  under  natural  (conditions  on  its  hoe»t.  At 
any  rate  the  exanii tuition  of  many  sfxits  has  faile<l  to  reveal  it.  Tints 
tlie  taxononiir  iN)siti(»n  of  the  fungus  is  problematical.  Until  these  two 
fzi'iM-ni  are  more  <'learly  <ietined  it  will  U*  calletl  provisionally  an  Altemana. 

To  what  >|MTies  the  fungus  should  U»  refiTred  was  a  matter  ef  doubt  for 
>oini-  time.  A  rareful  M'areh  of  the  literatun*  failtnl  to  reveal  a  <lesrnf>- 
lion  of  a  s|M'rirH  of  Altemaria  on  Patura.  One  Macmsporium.  M.  #ij- 
tunt    Taut.    ■  I^iinUtttr  and    Fautrey    1 8*. M >,  is  d(B<TtlM»d  as  occurring  tm 


1917]  Randb:  Altehnakia  on  Datdba.  and  Potato  335 

Datura  stramonium  on  the  sterile  spots  of  an  undetermined  gpeciee  of 
Sphaeropsidales 

The  Bpore  measurements  (150  to  190  by  18  to  20  >i)  fall  within  those 
given  in  this  paper  and  the  loi^  slender  "  pedicel"  (referring  to  the  termi- 
nal beak)  also  is  characteristic  of  the  fmiguB  under  consideration.  While 
it  is  probable  that  the  two  may  be  identical  the  description  is  entirely  too 
brief  for  one  to  be  certain.  The  question  was  referred  to  Dr.  J.  J.  Davis. 
After  looking  over  the  various  fungi  described  for  Datura,  he  expressed 
the  belief  that  this  Altemaria  (or  Macrosporium) ,  in  an  immature  condi- 
tion, was  probably  the  same  which  Saccardo  (1877  b)   describes  under 


Fia.  3.  Sevsn-Dats-Old  Coltdreb  of  Alternaria  Solani  (left)  and  Alterkaria. 

CRASBA    (rIOHT) 

The  colony  in  the  former  ie  light  brownish  and  produces  a  pinkish  diacoloratioit 
of  the  Agar  (bard  potato)  often  extending  in  advance  of  the  mycelium;  the  colony- 
of  the. latter  is  grayish  white  and  there  is  no  discoloration  of  the  medium. 

the  name  Cercospora  crassa  Ss.cc.  sp.  n.  He  also  found  that  later  Peck 
(1882)  describes  under  the  name  Cercospora  dalurw  n.  sp.  from  New  York 
State  what  seems  to  be  the  same.  The  fungus  corresponds  with  Peck's 
description  in  all  essentials  except  that  the  spore  measurements  (50  to 
75  by  12  n)  fall  considerably  short.  The  type  specimens  collected  by  Peck 
have  been  examined  and  the  appearance  of  the  spot  leaves  little  doubt 
of  their  identity  with  the  Madison  material.  From  Saccardo's  original 
illustration  (1877  a)  and  the  description  in  Michelia  where  the  spore  meas- 
urements are  given  as  100  to  150  by  15  to  18  **,  there  is  every  evidence 
that  he  was  dealing  with  immature  material  of  this  same  fungus.    In 


336 


Phytopathology 


[Vol.  7 


order  to  relieve  all  doubt,  however,  a  type  specimen  distributed  in  Myro- 
theca  Italica  No.  090  Padova.  August  1901  was  examined.' 

This  well-preserved  specunen  of  a  spotted  leaf  of  Datura  atramontum 
collected  by  Saccardo  was  s  milar  in  almost  every  respect  to  specimens 
from  Madison  and  from  various  other  parts  of  this  countr>'.  Though 
the  spots  are  small,  their  characteristic  appearance  leaves  no  doubt  of  the 
identity  of  the  two  diseases.  Furthermore,  some  spores  were  obtaincHl 
from  the  spec*imen  and  they  add  still  further  confirmation.     As  the  pn*9^ 


Via.  4.  CoMPAHisoN  OK  Spork  C*ii.\ka(^kkh  or  Altkknaria  tka-sha  and  Alti  nWKl * 

HOLANI 

In  thr  KctMip  tif  A.  rniHAii  (to  tho  U*ft :  the  firnt  two  arc  typical  uporrs  from  lf*.if- 
H|M)t  oil  Datura  Htraiiiniiiuin;  tlu>  third  rcprcmMits  .i  rnAc  of  rAtcnuIntion  on  a<-i«l'i- 
iHtnl  (MitHto  iifiiiT.  To  the  right,  typical  HporcH  of  A.  iiolaiii  Hhowing  van.itinn  in 
niic  Hiiii  ffinii:  tht'M*  an*  uiiifonnly  Htnnllcr  thnn  A.  craiwa  and  fn*qiic*ntly  bav«*  thr 
iM'nkit  )>rnnrhrti.      >:  3N). 

vurv  of  l<)ii)i[itii(linal  S4'pta  in  Ioiik  fKuntiMl  single  sfMrn^s  of  Alternana  or 
Marn»|N>riuin  is  the  imfK)rtunt  cluinicter  which  M*parat4*s  them  fn»in 
('<Tro<«|H>r:i.  it  may  In*  n*mlily  iindcrst<N)d  how  immatun*  s|Min*s  of  thr 
furincr  inii^ht  In*  mistaken  for  the  latt4'r.  .\nd  Saccanio  olis<'r\'(*<i  a  longi- 
tudinal si'ptuiii.  as  is  shown  bv  his  illustration,  but  he  calls  it  a  fal^*  oih*. 
**H-ptulo  ^purio."  Sint-e  it  is  true  that  the  lonKitutiiiuil  |mrtitioii>  m 
.'Mtcmaria  an'  p*iHTally  abs4*nt  until  the  sfMm's  attain  full  siie,  it  Mvnis  prt*l*- 
ablr,  a>  Dr.  Pavis  sufj^i^t'sts.  that  Saecardo's  c*onreption  was  obtamini 
from  iiiiinaturr  material. 


*   I  III-  unt«r  i<4  iiitlrtitfd  \n  |)r    A.  H.  Stout  of  thr  N«*w  York  Itotanical  tiardm 

fur  .i^-*l*>t  ilii  1    III  tti;tktllie  thl*»  ('\:illliliatli>ll. 


1917]  Rands:  Alternaria  on  Datura  and  Potato  337 

Cercospora  crassa  is  listed  by  Tassi  (1906)  at  the  University  of  Senna, 
,  Italy,  and  also  by  Ferraris  (1910  who  gives  as  its  distribution  northern 
Italy,  Switzerland,  and  Germany.  The  latter  describes  in  addition  the 
following  which  he  considers  forms  of  Cercospora  crassa:  (1)  lunarice,  on 
Lunaria  biennis;  (2)  ihiridiSj  on  76ms  umbeUata;  (3)  solani-^igri,  on  So- 
lanum  nigrum. 

These  are  recorded*  from  Italy  alone.  The  inoculations  already  de- 
scribed show  that  Solanum  nigrum  cannot  act  as  a  host  for  this  fungus, 
thus  throwing  some  doubt  on  the  vaUdity  of  the  form  reported  for  this 
plant.    No  tests  were  made  on  the  other  plants. 

In  order  to  avoid  future  confusion  the  probable  synonomy  of  the  fun- 
gus and  a  description  of  the  new  combination  are  here  given: 

Alternaria  crassa  (Sacc.)  n.  comb.' 

Cercospora  crassa  Ssicc.    Michelia  1 :  88.     1877. 

Cercospora  daturcs  Peck.    Rept.  New  York  State  Museum  35:  140.     1882. 
Macrosporium  solani  Cooke  (in  part).    Grevillea  12:  32.     1883. 
Macrosporium  datura  Fautrey.    Rev.  Myc.  16:  7B.     1894. 

Alternaria  solani  (E.  &  M.)  Jones  &  Grout  (in  part).    Bui.  Torr.  Bot.  Club, 
24:257.     1897. 

Conidiophores  I'ght  brown,  erect  or  ascending,  somewhat  irregular, 
septate,  generally  2  to  3  cespitose,  70  to  90  by  9  to  10  /i;  conidia  light 
brown,  obclavate,  with  very  long,  septate,  filiform,  terminal  beak,  gener- 
ally much  exceeding  in  length  the  body  of  the  spore,  total  dimensions 
128  to  448  by  16  to  40  m,  average  261  by  23  /i;  body  of  spore  56  to  140  m 
in  length,  7  to  9  transverse  septa,  1  to  3  longitudinal  septa  in  mature 
spores  (sometimes  absent);  colony,  in  potato  agar  culture,  Ught  grayish, 
cottony,  no  pigmentation  of  the  medium. 

Destructive,  causing  a  leaf-spot  and  pod  bUght  of  Jimson  weed  {Datura^ 
various  species). 

University  of  Wisconsin 
Madison,  Wisconsin 

*  Inasmuch  as  the  fundus  in  nature  produces  spores  singly,  and  catenulate  spores 
have  been  observed  only  in  culture,  some  authors  may  prefer  the  combination  Af  oc- 
rosporium  crassa.    ' 


338  Phytopathology  [Vol.  7 

LITERATURE  CITED 

Atkinson,  G.  F.    Some  fungi  from  Alabama.    Cornell  Univ.  Bui.  3:  40.     1997. 
Briosi,  G.  and  Cavara,  F.    Funghi  parassiti;  fasc.  VII,  VIII.    Pavia,  1992.       liiC 

Jahresh.  90:  176.     1892.) 
Chester,  F.  D.    A  leaf  bliRht  of  the  potato,  Macrosporium  aolani  K.  A  M.    IVLi- 

ware  Agr.  Exp.  Sta.  Rcpt.  4  (1891):  5H-60.     1892. 
Cooke,  M.  C.    New  Ajiicrican  fungi.    Grevillea  12:  32.     1883. 
Ferraris,  T.    Flora  Italica  cryptogama  pars  1:441.    1910. 

I  parassiti  vegetali  dclle  piantc  coltivate  od  utili.  pp.  892-893.     1913. 

Halrted,  H.  D.     Weeds  and  their  most  common  fungi.    New  Jersey  Agr.  Kxp  Stt 

Kept.  IS  [18921:348..    1893. 
Jones,  L.  H.    The  new  potato  disease  or  early  blight.     Vermont  Agr.  Kxp.  Sta 

Kept.  6  11892]:  G6.     1K93. 
Jones,  L.  H..  andCtKocr,  \.  J.     Nutcs  on  two  species  of  .\lternaria.     Hul.  Torr.  B«it. 

Club  24:  257.     1S<«. 
Kkllerman,  W.  a.    a  partial  list  of  the  Kansas  parasitic  fungi,  together  with  thrir 

host  plants.     Kansas  Acad.  Sci.  Trans.  9:  H3.     Aliui  Wash.  I^b.  Hul.  1 :  7S. 

1H8.5. 
L.\mhotte.  K.,  and  Favtrey,  F.     Ksp<Ves  nouvellesde  la  (Yue  d'Or.     Rev    Myc. 

16:  70.     1S94. 
Orton,  W.  .\.     .\  second  partial  liHt  of  the  parasitic  fungi  of  Vermont.     Vermont 

Agr.  Kxp.  Sta.  Kept.  12:  179.     1H<K».     Also  Contr.   liot.  Vermont  7:  179. 

ISIK). 

Vkck,  (\  U.     He|H)rt  of  the  liotanist.     New  York  State  .Museum  Kept.  31:  140. 

1SS2. 
SAct'ARDo,  P.  .\.     (a)  Fungi  rtalici  aut4igraphice  delineati.     No.  09.     1877. 

(b^  (Vrcoi!p*)ni  crassa  Sacc.  .Michelia  1:  HS.     1877. 

Sa(X'ari>o,  1*.  \.    Macros|M>riuiii  cookei  Sacc.    Sylloge  fungorum  4:  530.     IHM). 

Stkvenh,  F.  L.    Ohio  parasitic  fungi.    Ohio  State  Acad.  Sci.  Kept.  4:  23.     1K9C. 

Tas.hi,  Flaminio.  Klcnco  generale  dei  funghi  della  provincia  Senese  rinvenuti 
fino  a  tutto  Tanno  IWh.     l^ib.  Ort.  Bot.  Siena  Bui.  8:  226      1906. 

I'nderwood,  L.  .M.,  and  Karlk,  F.  S.  A  preliminary  list  of  .Vlabama  fungi.  .Ala- 
bama Agr.  Kxp.  Sta.  Bui.  KO:  155.     1H97. 


SUSCEPTIBILITY  OF  NON-CITRUS  PLANTS  TO   BACTERIUM 

CITRI 

R.    A.    J  E  H  L  E 

With  Three  Figures  in  the  Text 

Various  non-citrus  plants  have  been  inoculated  with  pure  tested  cul- 
tures of  Bacterium  Citri  Hasse  in  order  to  determine  their  susceptibility 
to  the  citrus  canker  disease.  Special  attention  has  been  given  to  related 
species  belonging  to  the  Rue  family  (Rutaceae).  The  plants  are  growing 
directly  in  the  soil  in  a  securely  screened  inclosure.  No  results  have  been 
obtained  from  any  of  these  experiments  excepting  in  the  case  of  Murraya 
exotica  (Orange  Jessamine)  and  Zanthoxylum  fagara  (L.)  Sarg.  (Wild-lime). 

In  the  case  of  Murraya  exotica  a  few  watery  swellings  developed  around 
some  of  the  needle-prick  inoculations  in  the  leaves  and  the  canker  organ- 
ism was  recovered  from  the  interior  of  one  of  the  swellings  a  few  weeks 
later.  Inoculations  were  also  made  by  spraying  the  twigs  and  leaves 
with  a  suspension  of  canker  bacteria,  but  the  results  of  these  latter  tests 
were  negative. 

Many  inoculations  were  made  on  the  twigs  of  all  sizes  and  on  the  leaves 
of  Zanthoxylum  fagara.  On  the  leaves  watery  swellings  sometimes  sur- 
roimded  by  a  yellow  halo  developed  around  most  of  the  needle-pricks  into 
which  canker  bacteria  were  introduced  (fig.  2,  A).  These  swellings  never 
burst  open,  but  Bacterium  Citri  was  recovered  from  the  interior  three 
months  after  inoculation.  On  the  twigs  a  total  of  about  one  hundred 
needle-prick  inoculations  were  made.  In  every  case  watery  swellings 
developed  in  about  ten  days.  These  swellings  on  the  twigs  continued  to 
increase  in  size  and  finally  longitudinal  splitting  of  the  bark  took  place 
exposing  a  mass  of  corky  cells  much  resembling  canker  infections  on  the 
twigs  of  Citrus  trifoliata  (figs.  1  and  3).  Bacterium  Citri  was  repeatedly 
recovered  from  these  swellings,  which  produced  typical  canker  on  grape- 
fruit seedlings  (fig.  3,  D  and  E),  On  Zanthoxylum  fagara  twigs  the  same 
organisms  produced  infections  identical  with  those  from  which  they  were 
isolated.  Check  inoculations  were  made  by  pricking  the  tissues  with  a 
sterilized  needle,  but  the  wounds  soon  healed  over  (fig.  1,  C). 

Twigs  of  Zanthoxylum  fagara  were  inoculated  by  spraying  a  suspension 
of  B,  Citri  in  distilled  water  on  the  uninjured  surface  with  an  atomizer. 
These  twigs  were  covered  for  several  days  with  a  lamp-chimney  plugged 


340 


Phytopatiioumiy 


[Vol.  7 


I  !■.    1    i:f-»ii"i  \i  I  HI  I -l*iiii  k  I\iM  I  i.Mi 'N- wi  III  HuTKitn  w  C'lTiii  IN  T»i«i' 

<i|     /  \\  I  liiiX^  I  1   M    I  \i.  M(\ 


1      I  -.4 II  iiifn  •:••[  >•  ••Ti  ;i  \i.  :!ii:  t  \\  i^;  Ml' /•I'l'^.nj 7/iitM  Nji/iiru  |iriNliii-i'«l  liy  iittriMiiir- 
.T.fcj /•'.    •      .'.'  ;ti'  .1''   t  i-xiio  \\  I' fi  .1  >!i-rili/i-il  iii'i-illi*.       •   !{.     'I'hi*  Inn  t-r  li-«i'in 

;i  i:  ■  -•   •  :.■  .T    .1  >   ri-    •     ;l'        I  ii-'i 'sla'i  ■!   \ii\  finlM-r  Jl».  l'.tl*»       l*liii1iiKr!i|ih  Ili3<i«    }»'- 

I  ~ 

•   •       ■    _ .     I'll 

/."     I  ■ '■     •:•"•       ■■■.•    ■.!!    ■    •■•ji:  t.f   /,'t} 'i.'-i  (l-tm  /iii/iir*!  iiriiiliiri-il   l»y  intr<N|>ii  :ri( 

/  '  .!■■•■.•        ..-A  I'll  I -fi  nii/«il  iiniilf       ■   :t      IimruLiivd  Niiit  ini^r 

)'■  ■■■■■J' ■!.■    '.      -i.    .liii;.iT\  J7    l'«I7 

'       '•■  ■  :  '     .  -  :i.    .!.'.   ^  ■./■»•'••■■..'  4".  ■"■:!/.;? fi  ml <i  wliifh  li<i  iir|C:iiii«{ii«  »•  rr 

:••..:  !'■        -    I.,  ill     \..'..  r-i'-i  •    .■*».    I'»lii       IMii>li«k;r.ip)ii-«l    J.iii  .  .-\    .T. 


1917]  Jehle:  Citrus  Canker  343 

with  cotton  at  the  ends.  Other  twigs  were  treated  in  exactly  the  same 
manner  excepting  that  sterilized  water  containing  no  B.  Citri  was  Used 
in  the  atomizer.  No  swellings  developed  on  the  twigs  sprayed  only  with 
sterilized  water  but  five  cankers  developed  on  the  twigs  sprayed  with 
B.  Citri.  The  five  cankers  which  developed  as  a  result  of  the  atomizer 
inoculations  were  almost  identical  in  appearance.  They  very  much 
resembled  young  citrus  canker  infections  on  the  twigs  of  Citrus  trifoliata, 
but  differed  from  the  latter  in  having  a  distinct  transverse  split  across  the 
center.  In  one  instance  the  development  of  one  of  these  cankers  was  ob- 
served for  several  months.  When  the  infection  was  found  it  was  a  small 
dark  green  watery  swelling  with  a  small  transverse  split  in  the  bark  across 
the  center.  The  swelling  continued  to  increase  in  size,  and  the  transverse 
split  in  the  bark  became  more  conspicuous.  When  the  canker  had  reached 
about  three  millimeters  in  diameter,  longitudinal  splits  began  to  appear 
in  the  bark  at  the  outer  ends  of  the  transverse  split.  The  cracks  exposed  a 
corky  mass  of  cankerous  tissue  similar  to  that  on  other  hosts.  The  largest 
canker  reached  a  diameter  of  five  millimeters  seven  months  after  inocu- 
lation. It  was  surrounded  by  an  oily  zone,  indicating  that  the  bacteria 
were  still  alive  and  active  in  the  interior.  One  of  the  smallest  cankers 
was  removed  from  the  tree  (fig.  3,  C)  and  isolations  were  made  from  the 
interior.  The  bacteria  recovered  from  this  canker  did  not  differ  from 
other  strains  of  Bacterium  Citri,  They  produced  typical  citrus  canker 
on  grapefruit  seedlings  and  infections  on  Zanthoxylum  fagara  identical 
with  infections  produced  by  other  cultures  of  Bacterium  Citri- 

A  grapefruit  seedling  badly  infected  with  citrus  canker  was  set  so  that 
its  branches  interlocked  with  those  of  Zanthoxylum  fagara.  Infections 
identical  with  those  resulting  from  inoculations  with  B,  Citri  have  de- 
veloped on  iminoculated  twigs  and  leaves  of  tanthoxylum  fagara  near  to 
the  infections  on  the  grapefruit  seedling.  These  infections  imdoubtedly 
resulted  from  B,  Citri  washed  by  rains  from  the  infected  grapefruit  tree 
to  the  twigs  and  leaves  of  Zanthoxylum  fagara. 

Fig.  3.  Result  of  Inoculations  with  Bacterium  Citri  on  Three  Different 

Hosts 

A.  Result  of  an  atomizer  inoculation  with  Bacterium  Citri  on  a  twig  and  thorn  of 
Citrus  trifoliata,     X  3. 

B  and  C.  Result  of  atomizer  inoculations  on  twigs  of  Zanthoxylum  fagara.  X  3. 
Both  twigs  inoculated  November  17,  1916. 

Bf  photographed  July  18,  1917;  C,  photographed  February  14,  1917.  Isolations 
were  made  from  C  on  February  15,  1917  and  pure  cultures  of  Bacterium  Citri  were 
recovered. 

D  and  E.  Result  of  needle-prick  inoculations  on  twigs  of  grapefruit  with  organ- 
isms recovered  from  interior  of  canker  on  a  twig  of  Zanthoxylum  fagara,     X  3. 


344  Phytopathology  [Vol  7 

Although  lesions  have  been  occasionally  noted  on  the  twig}>  of  Zan- 
thoxylum  fagara  in  Dade  County  hammocks,  they  have  been  I'arefully 
examined  and  no  evidence  has  been  secured  indicating  an  abundance  t»f 
natural  infestations  of  this  plant  with  the  bacteria  of  citrus  canker. 

Florida  State  I\.ant  Board 
Hedland  Tropical  Laboratory 


SOME  DISEASES  OF  ECONOMIC  PLANTS  IN  PORTO  RICQ 

L.  E.  Miles 
With  Three  Figures  in  the  Text 

ISARIOPSIS  ON  THE  BEAN 

The  Isariopsis  leaf -spot  of  the  cultivated  bean  is  a  disease  which  occurs 
on  both  the  foliage  and  pods  of  the  bean  plant,  often  resulting  in  consid- 
erable damage  to  the  crop,  due  to  the  lessening  of  the  active  leaf  surface 
or  sometimes  to  the  partial  or  complete  premature  defoliation.  The  dis- 
ease has  not  been  considered  of  any  great  significance  commercially,  but 
according  to  Halstead^  it  is  much  more  common  in  the  United  States  than 
is  usually  supposed,  and  to  it  should  probably  be  ascribed  much  of  the 
trouble  formerly  attributed  to  other  fungi.  It  is  easily  confoimded  with 
the  leai-blotch  of  the  bean  (Cercospora).  The  chief  points  of  difference 
between  these  two  diseases  will  be  considered  later  in  this  paper. 

The  fungus  causing  the  disease,  Isariopsis  griseola,  was  first  described 
by  Saccardo  in  1877,  as  occurring  in  northern  Italy  and  southern  Austria. 
Briosi  and  Cavara  also  report  it  as  occurring  in  Italy,  and  it  is  represented 
in  their  exsiccati  by  a  specimen  collected  near  Pavia  in  1888.  In  the  ex- 
siccati  of  Rabenhorst,  Winter  and  Pazschke  a  specimen  is  found  collected 
near  Zurich  in  Helvetia.  Rabenhorst  reports  the  disease  as  occurring 
also  in  Belgium,  Poland  and  Argentina.  It  is  represented  in  the  collec- 
tion of  North  American  Fungi  of  Ellis  and  Everhart  by  a  specimen  col- 
lected by  J.  B.  Ellis  at  Newfield,  New  Jersey  in  1889.  In  the  Fungi 
Columbiani  of  Ellis  and  Everhart,  as  continued  by  E.  Bartholomew,  a 
specimen  is  found  collected  by  C.  L.  Shear  at  Takoma  Park,  Maryland,  in 
1906.  Halstead  of  New  Jersey  in  1901  reported  it  as  occurring  in  that 
state.  F.  L.  Stevens  of  the  University  of  Illinois  found  it  in  abundance  on 
beans  in  the  garden  of  the  Experiment  Station  of  Porto  Rico  in  1912  and 
1913.  It  is  also  represented  in  the  collection  of  J.  A.  Stevenson  by  a 
specimen  collected  at  Rio  Piedras,  Porto  Rico,  in  1916.  The  writer  has 
examined  specimens  collected  by  J.  L.  Sheldon  at  the  following  places  in 
West  Virginia:  Morgantown,  1904;  Martinsbiu-g,  1905;  Sink's  Grove  and 
Bull  Run  in  1906.  The  Plant  Disease  Survey  of  the  United  States  De- 
partment of  Agriculture  reports  it  as  having  been  noted  in  Monroe  and 

>  Halstead.  B.  D.    New  Jersey  Agr.  Exp.  Sta.  Bui.  151.    1901. 


346  Phytopathology  (Vol.  7 

Jackson  counties  of  the  same  state  in  1906.  Specimens  on  pods  were  also 
collected  in  Preston  Country,  Connecticut  in  this  same  year  by  (1.  P. 
Clinton.  In  1908  it  was  reported  as  having  caused  considerable  damaice 
to  pole  beans  and  some  injury  to  bush  Ix^ans  at  Central  Village  and  Vohin- 
town,  Connecticut.  In  this  case  the  pole  beans  were  killed  half  way  up 
the  poles.  The  writer  has  also  examined  specimens  collected  by  (i.  P. 
Clinton  at  Westville,  Connecticut  in  the  years  1902  and  1905.  During 
the  summer  of  1916  M.  F.  Barrus  found  it  occurring  on  beans  in  the  mar- 
ket at  Washington,  D.  (\,  and  the  writer  has  looked  over  some  material 
which  he  collected  that  same  year  at  Chevy  Cha.se,  Mar>'land.  Recently 
also  the  writer  examined  some  material  collected  near  Managua.  Nica- 
ragua, in  Central  Ain(»rica,  by  Mrs.  (i.  V.  Ix)ng«  who,  not  IxMUg  ac(iuainte<i 
with  the  (Iis(*as4\  gathered  spotted  leaves  of  the  lx»an  at  random.  Since 
all  the  leavers  gathered  showed  this  dis(»as<>,  it  is  prolmble  that  it  occun*  in 
that  locality  in  considcTahle  abundance. 

In  spite  of  this  general  world  distribution,  the  literature  cono^ming  the 
fungus  is  meagre.  With  the  exception  of  Ilalsteacrs  pri»viou.sly  men- 
tioned note  of  its  oeeurn^nee  and  a  similar  one  by  Clinton-  all  of  the  pul>- 
lishe<i  referencH's  to  it  are  brief  <lescriptions  of  the  s|>ecimens  in  exsieeati 
with  the  date  and  i)lae<»  of  eoll(»otion.  Furthermon»  the  tigun*s  and  dc*- 
seriptions  an»  not  in  aeeord.  Saecardo^  si)eaks  of  the  hypluie  which  con- 
titut4'  the  con»miuin  on  which  the  sfWH^s  are  Inmie  as  liaving  reflexwl 
tii)s  and  his  figure*  repres<»nts  this  character  as  Inking  ver>'  pronouncetl. 
Hriosi  and  Cavara^  have  the  only  other  figure  that  the  writer  haslieen 
able  to  find  with  the  <»xception  of  a  copy  of  Saccardo's  in  Comes'  text- 
b<K)k.  This  figun»  <io<»s  not  n»pn*s4»nt  the  tijw  jis  l>eing  at  all  retiexwl  an<i 
examination  of  the  s|M»cimen  of  Hriosi  and  Cavara  .shows  agreement  with 
their  figun*  in  this  resfx^ct.  In  all  the  material  that  the  writer  lias  exam- 
ined including  the  gn»ater  part  of  that  mentioned  pn»viously  in  this  paf^er 
no  n»flc»x(»<l  hyphae  have  lH*en  found. 

The  Isariopsis  leaf-s|K)t  is  different  from  the  other  diseases  of  the  U»an 
in  that  it  is  confined  more  exclusively  to  the  foliage,  though  in  one  or  two 
instances  it  has  U'en  n»iH)rted  its  occurring  on  the  po<is  also.  On  the 
under  side  of  the  leaf  an*  pnxluced  numenms  small  angular s|)ots without 
a  colore<l  l)order  of  any  sort  (fig.  1 ).  It  is  this  angularity  of  the  spots  an«i 
abs<»nc<»  of  a  colonel  lH)rder  that  diffen»ntiat<^  it  so  readilv  fn>m  the  leaf- 
blotch  of  the  lM»an  caus4*d  by  ('crcnHporn  cruenta.     In  this  latter  dist»ase. 

'  Clinton.  (;    IV.  ConniMtiriit  Ajfr   Kxp.  Sta.  Iti'pt.  190S:  30H. 
»  .<.i«i  ;inlo.  P   A      S>IIoK«-  Kiinic'»nini  4:  tytt).     1H7S. 

*  StuvAniiK  V    \       FiinKi  Italiri.  rr;   s:r.      |S7S 

*  lini»?»i  .trhi  (*:iv:ir:i.     FiiriKhi  IVirii.Hsiti  »l«»llt»  IN.'tntr  (^uItiv.Hto  e<l  t'lili.     F 
N»).  17.     IVivi.i.  ISSH. 


1917) 


Miles:  Diseases  of  Pohto  Rican  Plants 


347 


the  spots  are  less  angular  and  are  surrounded  by  a  pronounced  red-brown 
border.  The  middle  portions  of  the  spots  are  also  likely  to  fall  out  in  the 
older  specimens,  producing  a  shot^hole  effect.  The  angularity  of  the 
Issriopsis  spots  is  due  to  the  fact  that  they  are  bounded  and  limited  by 
the  small  veinlets  of  the  leaf.  In  youth  these  spots  are  covered  by  a  gray, 
moldy  coating  due  to  the  laige  number  of  spores  produced  but  as  the  spot 
ages  it  becomes  a  pronounced  light  brown.  On  close  observation  it  will 
be  seen  to  be  studded  with  small  dots,  the  coremia,  on  which  the  spores 
are  borne  in  large  numbers. 


Fio.  2.  IsARioPsis  Gribeola 
A,  mycelium;  B,  germinating  eporea;  C,  Coremia 

The  coremia  are  columnar  and  are  formed  of  rather  dark  brownish 
hyphae  closely  aggregated,  though  seemingly  not  at  all  united  with  each 
other  (fig.  2,  C).  The  members  of  the  fruiting  column  tend  to  separate, 
especially  with  age,  thus  indicating  that  the  structure  should  perhaps  not 
be  regarded  as  a  typical  coremium  at  all.  The  number  of  hyphae  in  a 
column  varies  considerably.  In  some  as  few  as  eight  hyphae  were  ob- 
served while  in  others  the  number  often  reached  thirty  or  forty.  The 
hyphae  are  continuous,  brownish,  becoming  paler  toward  the  tip  and  av- 
erage about  200  ji  in  length.  The  average  thickness  of  the  coremium  is 
from  20  to  40  li. 


348  Phytopatholooy  [Vol.  7 

The  conidia  are  borne  on  the  smooth  tipe  of  the  hyphae  which  consti- 
tute  the  coremium  (fig.  2,  C).  These  tips  commonly  spread  at  the  top, 
especially  in  the  older  specimens,  giving  a  capitate  appearance  to  the 
spore  cluster.  The  writer  was  unable,  however,  to  observe  the  reflcxrd 
tips  as  described  and  pictured  by  Saccardo.  The  conidia  are  light  gray 
in  color,  cylindrical  to  spindleform,  slightly  curved,  and  scarcely,  if  at  all, 
constricted.  They  measure  50  to  60  m  in  length  by  7  to  8  m  in  thicknens, 
and  are  1-  to  3-septate.  In  a  few  cases  they  become  4-septate.  The 
mycelium,  though  composed  of  crooked  and  branching  cells,  is  of  prac- 
tically uniform  diameter  throughout  (fig.  2,  A).  It  lives  in  the  leaf  tis- 
sues and  forms  darkstromata  in  the  cavities  beneath  the  stomata  and  from 
these  the  coremia  arise. 

On  germination  the  end  cells  only,  of  the  3-  or  4-septate  spores,  send 
forth  mycelial  hyphae.  These  young  hyphae  are  non-septate  in  the 
earlier  stages  and  in  a  short  time  begin  to  branch  as  shown  in  figure  2.  H, 

No  experimental  work  has  yet  been  done  with  reference  to  treatment 
of  the  diseases  prol)abIy  Ix^cause  it  has  not  been  considered  of  sufficient 
economic  importance.  However,  HaLstead  suggests  that,  owing  to  the 
superficial  character  of  the  fungus,  the  same  treatment  ordinarily  ap- 
plied to  the  leaf-blotch  or  the  rust  of  the  l)ean  would  probably  be  effective. 

Specimens  examined:  Kal>enhor8t,  Fungi  Kur.  3998;  Kunic,  Fungi 
8el.  595;  Kriosi  and  Cavara,  Funghi  Parassiti,  No.  17;  Saccardo,  P.  A.. 
Fungi  Ital.,  Fig.  8iJ7;  Thimion,  Herb.  Myc.  Sec.  G54;  Ellis  and  Everhart, 
Fungi  Columbiani,  24IM;  Ellis  and  Everhart,  North  American  Fungi, 
2487. 

Other  specimens  collected  by:  Sheldon,  J.  F.,  Morgantown,  W.  Va.. 
1186;  Martin.sburg.  W.  Va.,  1989;  Bull.  Run,  W.  Va.,  2696;  Sink's  (irtivo. 
W.  Va.,  2719;  Barms,  M.  F.,  Cluvy  Chase,  Md.,  9057;  Clinton.  C.  P.. 
Westville,  Conn.,  two  packets;  liong,  Mrs.  O.  V.,  Managua,  Nicaragua; 
Stevenson,  J.  A.,  Kio  Piedras,  Porto  Rico.  6198;  Stevens,  F.  L.,  Por*o 
Rican  Fungi,  Jayuya,  7108;  Managuez,  5989;  Dos  Bocas,  7382;  7952. 

CERCOBPORA    .VICOTIAXAE    E.    A    E.    ON    TOBACCO 

Tolmcco  is  thini  in  rank  among  the  exports  of  Porto Hico,  though  only 
a  small  iwirtion  of  the  area  of  the  island  is  devotinl  to  its  culture.  The 
CVrc<»siN)ni  (ii.seaM'  may  n^ult  in  great  damage  to  the  standing  tobacco. 
and  in  »<oiiie  instance;*  xhv  crop  may  In>  practically  ruine<l.  It  is  mniit 
abundant  on  the  lower  leave.*<.  ap|H'aring  as  brown,  circular  spot*,  from 
the  si»»  of  a  pin-head  to  a  cf»ntimeter  or  more  in  diameter,  thickly  scat- 
tenti  oviT  the  entin*  leaf  surface.  The  older  spots  are  bordered  by  a 
dark.  rais4><i  line,  and  xhv  vvuXoth  dr\'  up  and  liecome  white,  often  falling 


1917]  Miles:  Diseases  of  Porto  Rican  Plants  349 

away  and  leaving  irregular  holes.  The  leaf  does  not  decay  as  a  result  of 
the  spotting,  but  turns  yellow  from  the  tip  downward  and  ripens 
prematurely. 

Dos  Bocas,  7980;  Ste.  Ana.  7612;  Quebradillos,  7270;  Caguas,  469; 
Cailes,  23. 

CERCOSPORA  HENNINGSII  ALESCH.  ON  CASSAVA 

Cassava,  Manihot  lUillismaj  is  cultivated  for  its  thick,  fleshy  root- 
stocks,  which  are  densely  stored  with  starch.  Although  it  is  not  used  in 
Porto  Rico  nearly  as  much  as  it  is  in  some  other  tropical  countries,  it  is 
cultivated  by  the  natives  to  some  extent  for  use  as  bread  and  for  the  starch 
which  it  contains.  Cercospora  henningsii  causes  a  small  dried-out  spot  on 
the  leaves,  but  it  is  of  but  little  importance,  as  it  probably  injures  the 
host  but  little. 

Hormigueso,  233;  Santurce,  254. 

CERCOSPORA  HIBISCI  TRACY  A  EARLE,  ON  OKRA 

Okra  is  cultivated  for  its  large  fruit  capsules  which  are  used  for  food. 
Cercospora  hibisd  occurs  on  the  lower  side  of  the  leaves,  not  in  spots,  but 
as  an  almost  continuous  coating.  It  causes  the  leaves  to  turn  yellow  and 
fall,  weakens  the  plant  and  reduces  the  quantity  of  pods. 

Quebradillas,  5030;  Aguadilla,  5229;  Cario  Raja,  6465. 

CERCOSPORA   CANESCENS   ELL.    &   MART.    ON    THE   BEAN 

Cercospora  canescens  does  some  damage  to  the  bean  crop,  due  to  small 
spots  on  the  upper  leaf  surface,  but,  as  a  rule,  it  does  not  prove  serious. 
Guayanilla,  5872. 

CERCOSPORA   COFFEE   ZIBCM.   ON   COFFEE 

Coffee  is  by  far  the  most  important  product  of  Porto  Rico.  Cercospora 
CoffeoB  causes  the  appearatice  on  the  leaf  of  spots  and  the  leaves  fall,  thus 
reducing  the  vitality  of  the  plant  and  preventing  the  proper  maturing  of 
the  berries.  These  spots,  as  a  rule,  are  round  or  oval  in  form,  clear  brown 
on  the  lower  side  of  the  leaf,  dark  brown  on  the  upper  side.  By  uniting, 
they  frequently  cause  large  blotches  which  dry  out  and  become  gray  in 
color  at  the  center.    Badly  infected  leaves  appear  more  or  less  brown. 

Afiasco,  3211;  Maricao,  4827. 

PUCCINIOPSIS  CARICiE  EARLE,  ON  THE  PAPAW 

The  tropical  papaw  [Carica  papaya)  is  attacked  by  a  leaf-spot  fungus, 
Puccinopsis  CariccB,  which  occurs  as  small,  erumpent,  black  masses  on 
the  under  side  of  the  leaf,  and  causes  more  or  less  yellowing  of  the  surround- 


350 


Phytopathology 


(Vol.  7 


ing  tissue.  The  attacke<l  leaves  die  and  fall  prematurely.  The  diM*a.*«r  i« 
not  destructive,  but  is  sometimes  reported  to  be  severe  on  young  neetlUng!*. 
Associated  with  the  causal  fungus  in  all  specimens  examined  by  the  au- 
thor was  found  a  ver>'  p(»culiar  fungus,  Zygosporium  oftchiouUn  Mont., 
which  is  represented  in  figure  3.  It  occurs  as  a  saproph>'te  on  the  Puc- 
ciniopsis  spots,  and  is  mentioned  here  only  on  account  of  its  ver>-  inten*?*!- 
ing  peculiaritii^  which  are  shown  in  the  figure. 
(Uianica,  .348;  Vega  Baja,  1913;  Mona  Island,  0,334;  6432. 


PHYLLA<'H<)IC\  (JR.\TIS8IMA  RKI1M.  OX  THE  AV(H'ADO 

This  fungus  raus4»s  jel-hlack,  erumfXMit  pustules  to  appear  on  the  up- 
|XT  side  of  the  leavi^sof  the  iwavixiXoiPersva  americana  Mill.).  The?*|M»t!* 
an*  from  one  to  two  inilliineters  in  diameter,  but  by  coalescing  they  may 
Imh'ouu*  considerably  larger.  The  injury  to  the  plant  is  pn>bably  not 
ver\'  gn»at. 

Javuva,  5974 ;  t*)()72. 


.MYCOSni.KllKLLA  PKKSE.E  MU-K